Time-of-check Time-of-use (TOCTOU) Affecting gvfs package, versions <1.54.4-0ubuntu1~24.04.4


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.17% (7th percentile)

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  • Snyk IDSNYK-UBUNTU2404-GVFS-19685048
  • published1 Oct 2026
  • disclosed10 Sept 2026

Introduced: 10 Sep 2026

NewCVE-2026-88924  (opens in a new tab)
CWE-367  (opens in a new tab)

How to fix?

Upgrade Ubuntu:24.04 gvfs to version 1.54.4-0ubuntu1~24.04.4 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream gvfs package and not the gvfs package as distributed by Ubuntu. See How to fix? for Ubuntu:24.04 relevant fixed versions and status.

A flaw was found in the admin backend of gvfs. The privileged gvfsd-admin daemon changes the ownership of newly created private D-Bus sockets by calling the link-following chown() function on a pathname inside a user-controlled directory. A local attacker can exploit this via a Time-of-Check Time-of-Use (TOCTOU) race condition and exchange the socket pathname with a symbolic link pointing to an arbitrary root-owned file (such as /etc/pam.d/su). The daemon subsequently follows the symlink and changes the ownership of the targeted root-owned file to the attacker's user ID. This allows an authenticated local attacker to modify critical system files, leading to a full local privilege escalation to root.

CVSS Base Scores

version 3.1