Ubuntu Security Advisories

It was discovered that the .NET Blazor WebAssembly debug proxy did not properly escape certain values. An attacker could possibly use this issue to execute arbitrary code. The fix for this CVE was originally released via USN-8942-1, but it was found to be incomplete. This issue only affected dotnet10 and dotnet11. (CVE-2026-102870) It was discovered that the Brotli decompression library used by .NET incorrectly handled certain compressed streams. A remote attacker could possibly use this issue to cause a denial of service or execute arbitrary code. (CVE-2026-111497) Alen Cheung discovered that .NET did not properly handle file ownership in certain circumstances. An attacker could possibly use this issue to elevate local privileges. (CVE-2026-114148)

USN-8956-1 fixed a vulnerability in Brotli. This update provides the corresponding fixes for Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. Original advisory details: It was discovered that Brotli incorrectly handled certain compressed streams. A remote attacker could possibly use this issue to cause a denial of service or execute arbitrary code.

Ali Mashally discovered that authd did not properly validate user identities when matching accounts from identity providers. An attacker could possibly use this issue to gain access to another user's local account and files, resulting in unauthorized access to sensitive information.

It was discovered that Brotli incorrectly handled certain compressed streams. A remote attacker could possibly use this issue to cause a denial of service or execute arbitrary code.

It was discovered that nginx incorrectly handled certain configurations using the alias directive together with rewrite rules. A remote attacker could possibly use this issue to cause nginx to crash, resulting in a denial of service, or execute arbitrary code. (CVE-2026-15176) It was discovered that nginx incorrectly handled map directives using regex matching under certain circumstances. A remote attacker could possibly use this issue to cause nginx to crash, resulting in a denial of service, or execute arbitrary code. (CVE-2026-93479) It was discovered that nginx incorrectly handled HTTP/3 requests when proxy_request_buffering was enabled. This issue only affected Ubuntu 26.04 LTS and Ubuntu 26.10. A remote attacker could possibly use this issue to inject data into proxied requests. (CVE-2026-95101) It was discovered that nginx incorrectly handled asynchronous file I/O in certain configurations with Server Side Includes pages. A remote attacker could possibly use this issue to cause nginx to crash, resulting in a denial of service, or execute arbitrary code. (CVE-2026-97205) It was discovered that nginx incorrectly handled SSL session ticket keys when configured with a shared session cache but without explicit ticket key rotation. This issue only affected Ubuntu 24.04 LTS, Ubuntu 26.04 LTS, and Ubuntu 26.10. A remote attacker could possibly use this issue to forge client SSL sessions and bypass client certificate verification. (CVE-2026-97629)

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.