========================================================================== Ubuntu Security Notice USN-7978-1 January 26, 2026
screen vulnerabilities ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 24.04 LTS - Ubuntu 22.04 LTS Summary: Several security issues were fixed in GNU Screen. Software Description: - screen: terminal multiplexer with VT100/ANSI terminal emulation Details: It was discovered that GNU Screen incorrectly handled signals when setuid or setgid privileges were being used, which is not the default in Ubuntu. A local attacker could use this issue to send privileged signals, possibly leading to a denial of service. This issue only affected Ubuntu 22.04 LTS. (CVE-2023-24626) It was discovered that GNU Screen incorrectly handled PTY permissions. A local attacker could possibly use this issue to connect to an unauthorized screen session. (CVE-2025-46802) It was discovered that GNU Screen incorrectly handled file access when setuid privileges were being used, which is not the default in Ubuntu. A local attacker could use this issue to deduce information about certain file paths. (CVE-2025-46804) It was discovered that GNU Screen incorrectly handled signals when setuid privileges were being used, which is not the default in Ubuntu. A local attacker could use this issue to send privileged signals, possibly leading to a denial of service. (CVE-2025-46805) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 24.04 LTS screen 4.9.1-1ubuntu1 Ubuntu 22.04 LTS screen 4.9.0-1ubuntu0.1 In general, a standard system update will make all the necessary changes. References: https://ubuntu.com/security/notices/USN-7978-1 CVE-2023-24626, CVE-2025-46802, CVE-2025-46804, CVE-2025-46805 Package Information: https://launchpad.net/ubuntu/+source/screen/4.9.1-1ubuntu1 https://launchpad.net/ubuntu/+source/screen/4.9.0-1ubuntu0.1
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