Ubuntu Security Advisories

Ali Firas discovered that zlib incorrectly handled certain non-blocking write operations. An attacker could possibly use this issue to trigger a heap buffer overflow, resulting in a denial of service or arbitrary code execution.

It was discovered that OpenVPN incorrectly handled certificate subject fields. A remote authenticated user could possibly use this issue to impersonate other users.

It was discovered that Tornado did not properly handle certain HTTP requests and network inputs. An attacker could possibly use these issues to cause a denial of service, expose sensitive information, or bypass access controls. (CVE-2023-54397, CVE-2024-14029, CVE-2026-91990, CVE-2026-91992, CVE-2026-103262, CVE-2026-103263)

USN-8890-1 fixed vulnerabilities in libsoup. This update provides the corresponding updates for libsoup3 on Ubuntu 26.10. Original advisory details: It was discovered that libsoup incorrectly handled certain HTTP/2 requests. A remote attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-4271) It was discovered that libsoup incorrectly handled certain HTTPS proxy connections. A remote attacker could possibly use this issue to obtain sensitive information. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-5119) It was discovered that libsoup incorrectly parsed certain chunked HTTP requests. A remote attacker could possibly use this issue to bypass security controls. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-6324) It was discovered that libsoup incorrectly handled proxy authentication credentials. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-66339) It was discovered that libsoup incorrectly handled certain HTTP Range headers. A remote attacker could possibly use this issue to cause a denial of service. (CVE-2026-77014, CVE-2026-77680) It was discovered that libsoup incorrectly handled certain HTTP/2 connections. A remote attacker could possibly use this issue to obtain sensitive information or execute arbitrary code. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-85197) It was discovered that libsoup incorrectly handled certain HTTP/2 transfers. A remote attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-85534)

It was discovered that c-ares incorrectly parsed certain SOA replies. A remote attacker could possibly use this issue to cause c-ares to crash, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2020-22217) It was discovered that c-ares incorrectly handled certain sortlist strings. A remote attacker could possibly use this issue to cause c-ares to crash, resulting in a denial of service, or execute arbitrary code. This issue only affected Ubuntu 16.04 LTS. (CVE-2022-4904) It was discovered that c-ares did not properly limit DNS compression pointer hops or assembled name lengths when parsing DNS names. A remote attacker could possibly use this issue to cause c-ares to use excessive resources, resulting in a denial of service. (CVE-2026-69184) It was discovered that c-ares did not properly validate record count fields before allocating memory when parsing DNS responses. A remote attacker could possibly use this issue to cause c-ares to use excessive resources, resulting in a denial of service. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-69186)

This update removes the "emSign ECC Root CA - G3" and "Comodo AAA Services root" CA certificate due to intermediate CA certificates being compromised.

It was discovered that poppler incorrectly handled the password length limit when decrypting certain encrypted PDF files. An attacker could possibly use this issue to cause a denial of service.

USN-8930-1 fixed some vulnerabilities in U-Boot. This update provides the corresponding fix for U-Boot on Ubuntu 26.10. Original advisory details: Shahriyar Jalayeri and Mehrun P. Hunter discovered that U-Boot incorrectly handled certain NFS READ and NFS READLINK responses. An attacker could possibly use this issue to trigger a buffer overflow, resulting in a denial of service or arbitrary code execution. (CVE-2026-74220, CVE-2026-74221) Shahriyar Jalayeri and Mehrun P. Hunter discovered that U-Boot incorrectly handled certain HTTP data storage failures in its lwIP implementation. An attacker could possibly use this issue to trigger a use-after-free, resulting in a denial of service. (CVE-2026-74222) Shahriyar Jalayeri and Mehrun P. Hunter discovered that U-Boot did not properly validate certain DHCPv6 option lengths during network boot. An attacker could possibly use this issue to trigger out-of-bounds memory access, resulting in a denial of service. (CVE-2026-74225)

Rick de Jager discovered that Ghostscript incorrectly handled memory under certain circumstances when processing PostScript documents. If a user or automated system were tricked into processing a specially crafted document, an attacker could possibly use this issue to bypass the sandbox and execute arbitrary code. (CVE-2026-101258) It was discovered that Ghostscript incorrectly handled memory when converting certain fonts. If a user or automated system were tricked into processing a specially crafted file, an attacker could possibly use this issue to cause Ghostscript to crash, or possibly execute arbitrary code. (CVE-2026-103226) Paulos Yibelo discovered that Ghostscript did not properly validate certain operands when loading fonts. If a user or automated system were tricked into processing a specially crafted file, an attacker could possibly use this issue to bypass the sandbox and execute arbitrary code. (No CVE number)

USN-8948-1 fixed vulnerabilities in Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 26.04 LTS and Ubuntu 26.10. This provides the corrosponding updates in Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. Original advisory details: It was discovered that PHP incorrectly handled out-of-memory conditions while processing requests. A remote attacker could use this issue to execute arbitrary code. (CVE-2026-109618) It was discovered that PHP incorrectly managed internal request state across worker reuse. A remote attacker could use this issue to execute arbitrary code. (CVE-2026-109619)

It was discovered that PHP incorrectly handled out-of-memory conditions while processing requests. A remote attacker could use this issue to execute arbitrary code. (CVE-2026-109618) It was discovered that PHP incorrectly managed internal request state across worker reuse. A remote attacker could use this issue to execute arbitrary code. (CVE-2026-109619)

It was discovered that Unbound incorrectly handled certain TCP connections. A remote attacker could possibly use this issue to cause Unbound to consume resources, leading to a denial of service. This issue only affected Ubuntu 26.04 LTS, Ubuntu 24.04 LTS, Ubuntu 22.04 LTS and Ubuntu 20.04 LTS. (CVE-2026-80225) It was discovered that Unbound incorrectly handled certain DNS responses. A remote attacker could possibly use this issue to crash Unbound, resulting in a denial of service. (CVE-2026-81634) It was discovered that Unbound incorrectly handled certain DNS responses during DNSSEC validation. A remote attacker could possibly use this issue to cause Unbound to consume resources, leading to a denial of service. (CVE-2026-85501) It was discovered that Unbound incorrectly handled outgoing network ports. A remote attacker could possibly use this issue to crash Unbound, resulting in a denial of service. (CVE-2026-50252) It was discovered that Unbound incorrectly handled certain DNSCrypt packets. A remote attacker could possibly use this issue to crash Unbound, resulting in a denial of service. This issue only affected Ubuntu 26.04 LTS, Ubuntu 24.04 LTS, Ubuntu 22.04 LTS, Ubuntu 20.04 LTS and Ubuntu 18.04 LTS. (CVE-2026-40691) It was discovered that Unbound incorrectly handled certain cached DNS responses. A remote attacker could possibly use this issue to poison Unbound's cache. This issue only affected Ubuntu 26.04 LTS, Ubuntu 24.04 LTS, Ubuntu 22.04 LTS and Ubuntu 20.04 LTS. (CVE-2026-44690) It was discovered that Unbound incorrectly handled certain DNS-over-QUIC connections. A remote attacker could possibly use this issue to cause Unbound to consume resources, leading to a denial of service. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-32665) It was discovered that Unbound incorrectly handled certain EDNS options. A remote attacker could possibly use this issue to crash Unbound, resulting in a denial of service. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-55973) Elias Heftrig, Haya Schulmann, Niklas Vogel, and Michael Waidner discovered that Unbound incorrectly handled validating DNSSEC messages. A remote attacker could possibly use this issue to cause Unbound to consume resources, leading to a denial of service. This issue only affected Ubuntu 18.04 LTS, Ubuntu 16.04 LTS and Ubuntu 14.04 LTS. (CVE-2023-50387) It was discovered that Unbound incorrectly handled preparing an NSEC3 closest encloser proof. A remote attacker could possibly use this issue to cause Unbound to consume resources, leading to a denial of service. This issue only affected Ubuntu 18.04 LTS, Ubuntu 16.04 LTS and Ubuntu 14.04 LTS. (CVE-2023-50868)

USN-8944-1 updated ca-certificates. This update provides the corresponding changes for Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS by removing the "emSign ECC Root CA - G3" and "Comodo AAA Services root" CA certificates. Original advisory details: This update removes the "emSign ECC Root CA - G3" CA certificate due to intermediate CA certificates being compromised. In addition, in Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS, the ca-certificates package contained outdated CA certificates. This update refreshes the included certificates to those contained in the 2.90 version of the Mozilla certificate authority bundle.

It was discovered that XZ Utils incorrectly handled certain memory allocation failures when reinitializing decoders for specific compressed file formats. An attacker could possibly use this issue to trigger an invalid memory write, resulting in a denial of service or arbitrary code execution.

This update removes the "emSign ECC Root CA - G3" CA certificate due to intermediate CA certificates being compromised. In addition, in Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS, the ca-certificates package contained outdated CA certificates. This update refreshes the included certificates to those contained in the 2.90 version of the Mozilla certificate authority bundle.

Multiple security issues were discovered in .NET and this update includes new upstream .NET versions to fix these issues. .NET 8 has been updated to 8.0.32 in Ubuntu 22.04 LTS and Ubuntu 24.04 LTS. .NET 10 has been updated to 10.0.13 in Ubuntu 24.04 LTS, Ubuntu 26.04 LTS and Ubuntu 26.10. .NET 11 has been updated to 11.0.0~rc2 in Ubuntu 26.10. In addition to security fixes, the updated packages contain bug fixes, new features, and possibly incompatible changes.

It was discovered that Protocol Buffers did not properly handle negative varint lengths or enforce recursion limits when parsing input in the PHP library. An attacker could possibly use this issue to cause applications using Protocol Buffers to crash or consume resources, resulting in a denial of service.

USN-8708-1 fixed a vulnerability in sudo-rs. This update provides the corresponding fix for Ubuntu 26.10. Original advisory details: It was discovered that sudo-rs incorrectly handled time-of-check vs time- of-use conditions in sudoedit. A local attacker with permission to edit specific files using sudoedit could use this issue to place files in arbitrary directories, and possibly escalate their privileges. This issue only affected systems configured to grant fine-grained sudoedit file editing permissions, which is not the default configuration.

It was discovered that Squid incorrectly handled certain HTTP Transfer- Encoding headers. An attacker could possibly use this issue to perform HTTP request smuggling attacks, bypass security mechanisms, or poison web caches. (CVE-2026-61642) It was discovered that Squid incorrectly handled certain cache digest replies, which could lead to a buffer overflow. A remote attacker could possibly use this issue to cause Squid to crash, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2026-50012) It was discovered that Squid incorrectly handled parsing certain FTP directory listings. A remote attacker could possibly use this issue to obtain sensitive information. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2026-47729) It was discovered that Squid incorrectly handled certain ICP traffic. A remote attacker could possibly use this issue to cause Squid to crash, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2026-32748, CVE-2026-33526) It was discovered that Squid incorrectly handled certain ICP requests. A remote attacker could possibly use this issue to obtain sensitive information. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2026-33515)

It was discovered that the Perl XS::Parse::Keyword module did not correctly handle certain inputs. If a user or automated system were tricked into receiving specially crafted input, an attacker could cause a denial of service.