SB2026092017 - openEuler 22.03 LTS SP4 update for util-linux

Description

This security bulletin contains information about 2 vulnerabilities.

1) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-53613)

CWE-ID: CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

CVSSv4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to a time-of-check time-of-use race condition in the mount target path handling in /usr/bin/mount when processing restricted non-root mount requests. A local user can atomically swap an ancestor directory of the mount target path between the permission check and the mount syscall to escalate privileges.

Exploitation requires an /etc/fstab entry with the user or users option where an ancestor directory of the mount target is writable by the attacker.

2) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-78410)

CWE-ID: CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to a time-of-check time-of-use race condition in restricted bind and rbind mount source handling in mount(8) when processing fstab-authorized bind mounts with X-mount.owner, X-mount.group, or X-mount.mode options. A local user can replace the authorized source path or a writable ancestor with a symlink to an attacker-selected directory to escalate privileges.

The issue affects SUID-root mount(8) restricted-user configurations where the authorized bind source is under a user-writable ancestor and the same fstab entry enables ownership or mode-changing post-mount hooks.

Remediation

Install update from vendor's website.

References

• https://www.openeuler.org/en/security/security-bulletins/detail/?id=openEuler-SA-2026-3979