https://ubuntu.com/security/notices/rss.xmlRecent content on Ubuntu security notices2026 Canonical Ltd. Ubuntu and Canonical are registered trademarks of Canonical Ltd.http://www.rssboard.org/rss-specificationFeedgenFri, 17 Jul 2026 02:37:23 +0000https://ubuntu.com/security/notices/USN-8477-2USN-8477-1 fixed a vulnerability in tar. The update introduced a regression that could cause tar to fail to extract certain valid files. This update fixes the problem. Original advisory details: 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.https://ubuntu.com/security/notices/USN-8477-2Thu, 16 Jul 2026 20:05:33 +0000https://ubuntu.com/security/notices/USN-8557-1Jay Neiva and Mauro Carrillo discovered that Authlib did not properly validate cryptographic keys embedded in JWT headers. An attacker could possibly use this issue to forge trusted tokens, resulting in authentication and authorization bypass. (CVE-2026-27962) Jay Neiva and Mauro Carrillo discovered that Authlib incorrectly handled RSA1_5 encrypted tokens. An attacker could possibly use this issue to recover sensitive encrypted information, resulting in information disclosure. (CVE-2026-28490) Jay Neiva and Mauro Carrillo discovered that Authlib did not properly reject unsupported cryptographic algorithms when validating OpenID Connect ID tokens. An attacker could possibly use this issue to bypass token integrity checks, resulting in authentication bypass. (CVE-2026-28498) Johnny Deuss discovered that Authlib did not provide cross-site request forgery protection for the OAuth cache feature in its Starlette integration. An attacker could possibly use this issue to perform unauthorized OAuth actions, resulting in cross-site request forgery. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-41425)https://ubuntu.com/security/notices/USN-8557-1Thu, 16 Jul 2026 17:44:41 +0000https://ubuntu.com/security/notices/USN-8556-1It was discovered that the Net::IMAP client in Ruby did not properly sanitize Symbol arguments passed to IMAP commands. A remote attacker controlling a malicious IMAP server, or able to influence command arguments, could use this to inject arbitrary IMAP commands via CRLF sequences. (CVE-2026-42258) It was discovered that the Zlib::GzipReader in Ruby did not correctly ensure sufficient buffer capacity in the zstream_buffer_ungets function. An attacker could use this to craft a gzip stream that, when processed, could cause a buffer overflow, resulting in memory corruption and possibly arbitrary code execution. (CVE-2026-27820)https://ubuntu.com/security/notices/USN-8556-1Thu, 16 Jul 2026 13:54:42 +0000https://ubuntu.com/security/notices/USN-8555-1Bilal Teke discovered that Ubuntu Advantage Tools exposed the Pro bearer token in command-line arguments when validating APT credentials. A local attacker could possibly use this issue to obtain sensitive information and gain unauthorized access to Ubuntu Pro repositories. (CVE-2026-9494) Frederick Jerusha discovered that Ubuntu Advantage Tools did not properly validate data received from the contract server when writing APT source files. An attacker could possibly use this issue to inject arbitrary APT configuration and execute arbitrary code. (CVE-2026-11386) Mateusz Gierblinski discovered that Ubuntu Advantage Tools did not properly handle symbolic links when collecting diagnostic logs. A local attacker could possibly use this issue to obtain sensitive information from files owned by the administrator. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-12391)https://ubuntu.com/security/notices/USN-8555-1Thu, 16 Jul 2026 12:59:08 +0000https://ubuntu.com/security/notices/USN-8554-1It was discovered that NTFS-3G had a heap buffer overflow when reading certain NTFS images. A local attacker could possibly use this issue to execute arbitrary code. (CVE-2026-42616) It was discovered that NTFS-3G had multiple heap buffer overflows when processing certain NTFS images. A local attacker could possibly use these issues to execute arbitrary code. (CVE-2026-42617, CVE-2026-42618, CVE-2026-46569, CVE-2026-46570, CVE-2026-46572, CVE-2026-56135) It was discovered that NTFS-3G had out-of-bounds reads when processing certain NTFS images. A local attacker could possibly use these issues to obtain sensitive information. (CVE-2026-46571, CVE-2026-56136)https://ubuntu.com/security/notices/USN-8554-1Thu, 16 Jul 2026 11:44:54 +0000https://ubuntu.com/security/notices/USN-8553-1Artur Stetsko discovered that the .NET did not properly validate authentication data. An attacker could possibly use this issue to elevate privileges. (CVE-2026-47300) Levi Broderick discovered that .NET did not properly handle XML encryption during parsing. An attacker could possibly use this issue to consume excessive resources, resulting in a denial of service. (CVE-2026-47302) Pham Quang Minh discovered that .NET did not properly parse authentication data. An attacker could possibly use this issue to bypass authentication and elevate privileges. (CVE-2026-47303) Levi Broderick discovered that .NET did not properly verify cryptographic signatures during XML encryption. An attacker could possibly use this issue to bypass security features over a network and access encrypted data. (CVE-2026-47304) It was discovered that .NET did not properly validate input during TLS handshakes. An attacker could possibly use this issue to cause .NET to crash, resulting in a denial of service. (CVE-2026-50524) Levi Broderick discovered that .NET did not properly handle resource allocation during XML encryption. An attacker could possibly use this issue to consume excessive resources, resulting in a denial of service. (CVE-2026-50525) Siwei Li discovered that .NET did not properly handle link resolution before file access during the container image build process. A local attacker could possibly use this issue to inject resources that could be incorporated into container images built by other users on the same machine. (CVE-2026-50526) Levi Broderick discovered that .NET did not properly handle memory while performing XML encryption. An attacker could possibly use this issue to cause .NET to crash, resulting in a denial of service. (CVE-2026-50527) Henrique Pereira discovered that .NET did not properly handle authorization checks during TLS/SSL connections. An attacker could possibly use this issue to bypass authorization checks during secure communications. (CVE-2026-50528) It was discovered that .NET did not properly handle resource allocation during XML encryption. An attacker could possibly use this issue to consume excessive resources, resulting in a denial of service. (CVE-2026-50648) Miha Zupan discovered that .NET did not properly limit resource allocation when handling HTTP/2 requests. An attacker could possibly use this issue to consume excessive resources, resulting in a denial of service. (CVE-2026-50651) It was discovered that the .NET SMTP client did not properly handle the encoding or escaping of output. An attacker could possibly use this issue to spoof messages during message routing. (CVE-2026-50659) It was discovered that .NET did not properly validate resource types when parsing X.509 certificates. An attacker could possibly use this issue to cause .NET to crash, resulting in a denial of service. (CVE-2026-57108)https://ubuntu.com/security/notices/USN-8553-1Wed, 15 Jul 2026 17:13:59 +0000https://ubuntu.com/security/notices/USN-8552-1It was discovered that Sympa did not properly validate input on the generic SSO login. A remote attacker could possibly use this issue to perform a path traversal attack and gain unintended access.https://ubuntu.com/security/notices/USN-8552-1Wed, 15 Jul 2026 14:50:01 +0000https://ubuntu.com/security/notices/USN-8551-1It was discovered that Tomcat incorrectly handled authorization when multiple method constraints defined the same HTTP method. A remote attacker could possibly use this issue to bypass authorization restrictions. (CVE-2026-43515) It was discovered that the Tomcat number guess example application did not properly sanitize user-supplied input. An attacker could possibly use this issue to inject malicious scripts, resulting in cross-site scripting. (CVE-2026-50229) It was discovered that Tomcat incorrectly evaluated rewrite valve conditions in certain configurations. An attacker could possibly use this issue to bypass rewrite rules, resulting in unauthorized access. (CVE-2026-53404) It was discovered that Tomcat incorrectly omitted certain authorization information when logging the effective web.xml configuration. An attacker could possibly use this issue to hide authorization constraints, resulting in reduced auditability. (CVE-2026-55276)https://ubuntu.com/security/notices/USN-8551-1Wed, 15 Jul 2026 14:15:28 +0000https://ubuntu.com/security/notices/USN-8550-1It was discovered that libslirp incorrectly handled TCP urgent data. A privileged attacker inside a guest VM could possibly use this issue to obtain sensitive information from the host process memory.https://ubuntu.com/security/notices/USN-8550-1Wed, 15 Jul 2026 13:59:22 +0000https://ubuntu.com/security/notices/USN-8549-1It was discovered that idna did not properly reject oversized inputs before performing expensive processing. An attacker could possibly use this issue to cause idna to consume significant resources, leading to a denial of service.https://ubuntu.com/security/notices/USN-8549-1Wed, 15 Jul 2026 13:46:50 +0000