CVE-2026-88924

Summary

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.

Affected Software

VendorProductVersion RangeStatus
GNOMEgvfs1.48.1 < 1.62.0affected
GNOMEgvfs1.48.1 < 1.60.3affected
GNOMEgvfs1.48.1 < 1.58.5affected
Red HatRed Hat Enterprise Linux 100:1.54.4-4.el10_2.1 < *unaffected
Red HatRed Hat Enterprise Linux 90:1.48.1-8.el9_8.1 < *unaffected

Weaknesses

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

Workarounds

To mitigate this issue, adjust Polkit rules to require password authentication to start gvfsd-admin or remove execute permissions of the gvfsd-admin binary to prevent execution.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: no
    • Technical Impact: total

Additional References

References