Ubuntu Security Advisories

It was discovered that libssh2 incorrectly handled the sftp_symlink() function. A malicious SSH server or machine-in-the-middle attacker could possibly use this issue to obtain sensitive information or cause a denial of service. (CVE-2025-15661) It was discovered that libssh2 had a pre-authentication denial of service vulnerability in the SSH_MSG_EXT_INFO handler. A malicious SSH server could possibly use this issue to cause a client CPU exhaustion loop, resulting in a denial of service. (CVE-2026-55199) It was discovered that libssh2 incorrectly handled packet length fields. A remote attacker could possibly use this issue to execute arbitrary code. This issue only affected Ubuntu 25.10 and Ubuntu 26.04 LTS. (CVE-2026-55200)

It was discovered that libyang incorrectly handled certain metadata list pointers. An attacker could use this issue to cause libyang to crash, resulting in a denial of service, or possibly execute arbitrary code.

It was discovered that GD.pm incorrectly handled filename arguments. An attacker could possibly use this issue to execute arbitrary commands or overwrite files.

It was discovered that HPLIP incorrectly handled certain print data. An attacker could possibly use this issue to cause HPLIP to execute arbitrary code. (CVE-2026-8631) It was discovered that HPLIP incorrectly handled certain inputs. A local attacker could possibly use this issue to execute arbitrary code. (CVE-2026-8632)

It was discovered that Roundcube Webmail was prone to a Cross-Site-Scripting (XSS) vulnerability via the animate tag in an SVG document. An attacker could use this issue to execute arbitrary web script in the context of an affected user's session.

Haruto Kimura discovered that NSS had incorrecty handled parsing PKCS#11 URI escape sequences. An attacker could possibly use this issue to cause NSS to crash, resulting in a denial of service, or obtain sensitive information.

It was discovered that SQLite incorrectly handled certain memory operations in the FTS5 full-text search extension. An attacker could use this issue to cause SQLite to crash, resulting in a denial of service, or possibly execute arbitrary code.

It was discovered that libheif incorrectly handled certain crafted HEIF files. An attacker could possibly use this issue to cause a denial of service or execute arbitrary code. (CVE-2026-47178) It was discovered that libheif incorrectly validated offsets when decoding certain crafted HEIF files. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-49271)

USN-8412-1 fixed vulnerabilities QEMU. On Ubuntu 20.04 LTS, the fix for CVE-2024-4467 was incomplete and prevented the creation of boot volumes from qcow2 images. This update fixes the problem. We apologize for the inconvenience. Original advisory details: Felipe Franciosi, Raphael Norwitz, and Peter Turschmid discovered that the iSCSI block driver in QEMU incorrectly handled certain responses from an iSCSI server. A remote attacker could possibly use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-1711) It was discovered that the iSCSI block driver in QEMU incorrectly handled certain memory operations, leading to a heap-based buffer over-read. An attacker could possibly use this issue to expose sensitive information from the host. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-11947) Ziming Zhang discovered that the SM501 display driver in QEMU contained an integer overflow. A local attacker could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-12829) Gaoning Pan and Xingwei Li discovered that the USB xHCI controller implementation in QEMU contained an infinite loop. An attacker inside the guest could possibly use this issue to cause QEMU to hang, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, and Ubuntu 18.04 LTS. (CVE-2020-14394) Lei Sun discovered that QEMU incorrectly handled certain MemoryRegionOps objects, leading to a NULL pointer dereference. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2020-15469) Alexander Bulekov discovered that the e1000e network device implementation in QEMU contained a use-after-free. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-15859) Ziming Zhang discovered that the XGMAC Ethernet controller in QEMU contained a buffer overflow. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-15863) Alexander Bulekov discovered that the SDHCI device emulation in QEMU contained a heap-based buffer overflow. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-17380) Sergej Schumilo, Cornelius Aschermann, and Simon Wörner discovered that the USB xHCI controller implementation in QEMU did not check a return value, leading to a use-after-free. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-25084) Gaoning Pan, Yongkang Jia, and Yi Ren discovered that the USB OHCI controller implementation in QEMU contained a stack-based buffer over- read. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-25624) It was discovered that the USB OHCI controller implementation in QEMU contained an infinite loop. An attacker inside the guest could possibly use this issue to cause QEMU to consume resources, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-25625) Cheolwoo Myung discovered that the USB EHCI emulation in QEMU did not handle DMA memory map failures, leading to a reachable assertion. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-25723) Gaoning Pan discovered that the network device emulation in QEMU could be made to trigger an assertion failure when processing packets that lacked a valid layer 3 protocol. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-27617) Wenxiang Qian discovered that the ATAPI emulation in QEMU did not properly validate a buffer index, leading to an out-of-bounds read. An attacker inside the guest could possibly use this issue to expose sensitive information or cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-29443) Cheolwoo Myung discovered that the ESP SCSI emulation in QEMU contained a NULL pointer dereference. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2020-35504) Cheolwoo Myung discovered that the am53c974 SCSI host bus adapter emulation in QEMU contained a NULL pointer dereference. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2020-35505) It was discovered that the SDHCI controller emulation in QEMU contained out-of-bounds read and write issues. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2021-3409) It was discovered that several network device emulations in QEMU contained an infinite loop when operating in loopback mode. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2021-3416) Alexander Bulekov discovered that the floppy disk emulation in QEMU contained a heap-based buffer overflow. An attacker inside the guest could possibly use this issue to expose sensitive information or cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2021-3507) Remy Noel discovered that the USB redirector device emulation in QEMU performed an unbounded stack allocation when combining USB packets. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2021-3527) It was discovered that the QXL display device emulation in QEMU contained an integer overflow, leading to a heap-based buffer overflow. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2021-4206) It was discovered that the QXL display device emulation in QEMU performed a double fetch of guest-controlled values, leading to a heap-based buffer overflow. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2021-4207) It was discovered that the 9pfs server implementation in QEMU contained a race condition, leading to a use-after-free. A malicious 9p client could possibly use this issue to escalate privileges. This issue only affected Ubuntu 14.04 LTS. (CVE-2021-20181) Gaoning Pan discovered that the floppy disk emulation in QEMU contained a NULL pointer dereference. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2021-20196) Gaoning Pan discovered that the vmxnet3 network device emulation in QEMU contained an integer overflow. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2021-20203) It was discovered that the ARM Generic Interrupt Controller emulation in QEMU contained an out-of-bounds heap access. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2021-20221) Alexander Bulekov, Cheolwoo Myung, Sergej Schumilo, Cornelius Aschermann, and Simon Wörner discovered that the e1000 network device emulation in QEMU contained an infinite loop. An attacker inside the guest could possibly use this issue to cause QEMU to consume resources, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2021-20257) It was discovered that the 9p passthrough file system implementation in QEMU did not prevent opening special files on the host. A malicious guest could possibly use this issue to escape the exported 9p tree. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, and Ubuntu 18.04 LTS. (CVE-2023-2861) It was discovered that the virtio crypto device emulation in QEMU did not properly validate certain buffer lengths, leading to a heap buffer overflow. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 18.04 LTS. (CVE-2023-3180) It was discovered that the built-in VNC server in QEMU contained a NULL pointer dereference when cleaning up a connection that failed during the handshake. A remote attacker could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 18.04 LTS. (CVE-2023-3354) It was discovered that QEMU could incorrectly direct a guest I/O operation to disk offset 0 instead of the intended offset. An attacker inside the guest could possibly use this issue to read or overwrite sensitive data, potentially gaining control of the host. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, and Ubuntu 18.04 LTS. (CVE-2023-5088) It was discovered that several virtio device emulations in QEMU did not properly guard against DMA reentrancy, leading to a double free. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2024-3446) It was discovered that the SDHCI device emulation in QEMU contained a heap- based buffer overflow. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. (CVE-2024-3447) It was discovered that the QEMU disk image utility (qemu-img) did not properly handle certain crafted image files. An attacker could possibly use this issue to cause qemu-img to consume excessive resources or access an unintended external file, resulting in a denial of service. This issue only affected Ubuntu 20.04 LTS. (CVE-2024-4467) Cyrille Chatras discovered that the LSI53C895A SCSI Host Bus Adapter emulation in QEMU contained a use-after-free. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2024-6519) It was discovered that the NBD server in QEMU contained an improper synchronization issue during socket closure. A remote attacker could possibly use this issue to cause QEMU to crash, resulting in a denial of service. (CVE-2024-7409) It was discovered that the USB emulation in QEMU contained a reachable assertion. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. (CVE-2024-8354) It was discovered that QEMU incorrectly handled resources during the VNC WebSocket handshake, leading to a use-after-free. A remote attacker could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2025-11234) It was discovered that QEMU could be made to read out of bounds when reading VMDK images. An attacker could possibly use this issue to expose sensitive information or cause QEMU to crash, resulting in a denial of service. (CVE-2026-2243)

It was discovered that tar incorrectly handled certain crafted archive files. An attacker could possibly use this to inject hidden files with attacker-controlled content, bypassing pre-extraction inspection mechanisms.

Oleksii Oleksenko, Cedric Fournet, Jana Hofmann, Boris Köpf, Stavros Volos, and Flavien Solt discovered that some AMD processors may allow an attacker to infer data from previous stores, potentially resulting in the leakage of privileged information. A local attacker could possibly use this to expose sensitive information. (CVE-2024-36350, CVE-2024-36357) It was discovered that some AMD Zen 5 processors supporting RDSEED instruction did not properly handle entropy, potentially resulting in the consumption of insufficiently random values. A local attacker could possibly use this issue to influence the values returned by the RDSEED instruction causing loss of confidentiality and integrity. (CVE-2025-62626)

It was discovered that xrdp incorrectly handled bounds checking when processing user domain information during the connection sequence. An unauthenticated remote attacker could use this issue to cause xrdp to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2025-68670) It was discovered that xrdp did not correctly enforce the maximum number of login attempts configured by the MaxLoginRetry parameter. A remote attacker could use this issue to perform an unlimited number of login attempts. (CVE-2024-39917) It was discovered that xrdp did not perform bounds checking when accessing font glyphs. Since some of this data is controllable by the user, a remote attacker could use this issue to cause xrdp to read out of bounds. This issue only affected Ubuntu 24.04 LTS. (CVE-2023-42822) It was discovered that xrdp did not properly handle session establishment errors. A remote attacker could use this issue to bypass OS-level session restrictions enforced by PAM, such as the maximum number of concurrent sessions per user. This issue only affected Ubuntu 24.04 LTS. (CVE-2023-40184)

It was discovered that containerd incorrectly handled HTTP/2 SETTINGS frames. A remote attacker could possibly use this issue to cause containerd to enter an infinite loop, resulting in a denial of service. (CVE-2026-33814) Jakub Ciolek and Kyle Elliott discovered that containerd incorrectly handled group parsing when creating containers from images. An attacker could possibly use this issue to cause containerd to consume excessive memory, resulting in a denial of service. (CVE-2026-47262) Henry Beberman and Robert Prast discovered that containerd incorrectly validated image references when importing container checkpoints. An attacker could possibly use this issue to poison the local image cache and execute arbitrary code in other pods. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 25.10 and Ubuntu 26.04 LTS. (CVE-2026-50195) Robert Prast discovered that containerd incorrectly propagated labels from image configurations to containers. An attacker could possibly use this issue to execute arbitrary code on the host. (CVE-2026-53488) Yuming Zhang, Song Li, Sangwon Ryu, Henry Beberman, Robert Prast, Kyle Elliott and Zhenchen Wang discovered that containerd incorrectly validated symlinked paths when restoring container checkpoints. An attacker could possibly use this issue to read arbitrary files on the host, resulting in information disclosure. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 25.10 and Ubuntu 26.04 LTS. (CVE-2026-53489) Robert Prast discovered that containerd incorrectly trusted device interface annotations when restoring container checkpoints. An attacker could possibly use this issue to bypass resource allocation restrictions and inject devices or host mounts into a container. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 25.10 and Ubuntu 26.04 LTS. (CVE-2026-53492)

It was discovered that containerd incorrectly handled HTTP/2 SETTINGS frames. A remote attacker could possibly use this issue to cause containerd to enter an infinite loop, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS and Ubuntu 22.04 LTS. (CVE-2026-33814) Jakub Ciolek and Kyle Elliott discovered that containerd incorrectly handled group parsing when creating containers from images. An attacker could possibly use this issue to cause containerd to consume excessive memory, resulting in a denial of service. (CVE-2026-47262) Robert Prast discovered that containerd incorrectly propagated labels from image configurations to containers. An attacker could possibly use this issue to execute arbitrary code on the host. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-53488)

It was discovered that containerd incorrectly handled HTTP/2 SETTINGS frames. A remote attacker could possibly use this issue to cause containerd to enter an infinite loop, resulting in a denial of service. (CVE-2026-33814) Jakub Ciolek and Kyle Elliott discovered that containerd incorrectly handled group parsing when creating containers from images. An attacker could possibly use this issue to cause containerd to consume excessive memory, resulting in a denial of service. (CVE-2026-47262) Henry Beberman and Robert Prast discovered that containerd incorrectly validated image references when importing container checkpoints. An attacker could possibly use this issue to poison the local image cache and execute arbitrary code in other pods. (CVE-2026-50195) Robert Prast discovered that containerd incorrectly propagated labels from image configurations to containers. An attacker could possibly use this issue to execute arbitrary code on the host. (CVE-2026-53488) Yuming Zhang, Song Li, Sangwon Ryu, Henry Beberman, Robert Prast, Kyle Elliott and Zhenchen Wang discovered that containerd incorrectly validated symlinked paths when restoring container checkpoints. An attacker could possibly use this issue to read arbitrary files on the host, resulting in information disclosure. (CVE-2026-53489) Robert Prast discovered that containerd incorrectly trusted device interface annotations when restoring container checkpoints. An attacker could possibly use this issue to bypass resource allocation restrictions and inject devices or host mounts into a container. (CVE-2026-53492)

It was discovered that NSD incorrectly handled APL resource records with an address length larger than permitted for the address family. A remote attacker could use this to cause a stack-based buffer overflow when the zone is written to disk, potentially executing arbitrary code with the privileges of the NSD server. (CVE-2026-12246) It was discovered that NSD incorrectly handled SVCB resource records. A remote attacker could use this to cause a heap overflow, potentially executing arbitrary code with the privileges of the NSD server. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-12244) It was discovered that NSD had a use-after-free vulnerability in TLS connection error logging. A remote attacker could use this to cause a denial of service by crashing the server process. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-12245) It was discovered that NSD incorrectly handled TLS authentication for zone transfers. An attacker could bypass transfer security restrictions when certain conditions were met. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-12490)

It was discovered that cpp-httplib incorrectly percent-decoded HTTP request header values. A remote attacker could use this to inject crafted header content possibly leading to response splitting, log injection or proxy smuggling.

It was discovered that ImageMagick incorrectly handled certain images when using the wavelet-denoise operator. An attacker could possibly use this issue to trigger a heap buffer over-read, resulting in information disclosure. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, and Ubuntu 24.04 LTS. (CVE-2026-27798) It was discovered that ImageMagick incorrectly handled certain DJVU images. An attacker could possibly use this issue to trigger a heap buffer over-read, resulting in information disclosure. (CVE-2026-27799) It was discovered that ImageMagick incorrectly handled certain MNG images. An attacker could possibly use this issue to trigger a stack buffer overflow, resulting in arbitrary code execution. (CVE-2026-28690) It was discovered that ImageMagick incorrectly handled certain JBIG images. An attacker could possibly use this issue to trigger a pointer dereference error, resulting in a denial of service. (CVE-2026-28691) It was discovered that ImageMagick incorrectly handled certain MAT images. An attacker could possibly use this issue to trigger a heap buffer over-read, resulting in information disclosure. (CVE-2026-28692) It was discovered that ImageMagick incorrectly handled certain DIB images. An attacker could possibly use this issue to trigger an integer overflow, resulting in arbitrary code execution. (CVE-2026-28693)

Jiasheng Jiang discovered that FFmpeg incorrectly handled memory in certain error-handling paths of its TensorFlow DNN backend. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 24.04 LTS. (CVE-2025-12343) Quang Luong discovered that FFmpeg incorrectly handled certain subsample data. An attacker could possibly use this issue to cause a denial of service or possibly execute arbitrary code. (CVE-2026-40962)

It was discovered that Perl's Archive::Tar module incorrectly handled symlink and hardlink targets during extraction. An attacker could use this issue to read or overwrite arbitrary files outside the extraction directory. (CVE-2026-42496) It was discovered that Perl had a heap buffer overflow when compiling regular expressions with a repeated fixed string on 32-bit builds. An attacker could use this issue to cause a denial of service or possibly execute arbitrary code. (CVE-2026-8376)