USN-8702-1: util-linux vulnerabilities

It was discovered that libblkid in util-linux had a heap use-after-free vulnerability during nested partition probing. An attacker who could present a crafted block device image could possibly use this issue to obtain sensitive information or cause a denial of service. (CVE-2026-13595) It was discovered that the mount utility in util-linux had a time-of-check- time-of-use vulnerability when setting up loop devices. A local attacker could possibly use this issue to obtain unauthorized read access to root- protected files and block devices. (CVE-2026-27456) It was discovered that the login utility in util-linux improperly canonicalized hostnames when invoked with the -h option. A remote attacker could possibly use this issue to bypass host-based access control rules. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-3184) It was discovered that libmount in util-linux had a time-of-check-time-of- use vulnerability in its ownership hook. A local attacker could possibly use this issue to gain elevated privileges. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-53612) It was discovered that libmount in util-linux had a time-of-check-time-of- use vulnerability that allowed target path redirection during mount operations. A local attacker could possibly use this issue to gain elevated privileges. (CVE-2026-53613) It was discovered that libmount in util-linux improperly handled the LIBMOUNTFORCEMOUNT2 environment variable in the SUID mount utility. A local attacker could possibly use this issue to bypass nosuid and noexec mount options and gain elevated privileges. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-53614) It was discovered that libblkid in util-linux had an integer overflow vulnerability when parsing DOS partition tables. An attacker who could present a crafted block device image could possibly use this issue to cause a denial of service. (CVE-2026-53615)