| Name | CVE-2026-54370 |
| Description | acl before version 2.4.0 contains a time-of-check to time-of-use (TOCTOU) race condition vulnerability that allows local attackers to escalate privileges by replacing a pathname component with a symbolic link between an lstat() check and subsequent symlink-following operations such as stat(), chown(), chmod(), acl_get_file(), and acl_set_file(). Attackers who control a pathname component can redirect file access control list operations to arbitrary files when getfacl, setfacl, or chacl is invoked by a privileged process over an attacker-controlled path, resulting in local privilege escalation. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| Debian Bugs | 1141110 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| acl (PTS) | bullseye | 2.2.53-10 | vulnerable |
| bookworm | 2.3.1-3 | vulnerable | |
| trixie | 2.3.2-2 | vulnerable | |
| forky, sid | 2.4.0-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| acl | source | (unstable) | 2.4.0-1 | 1141110 |
[trixie] - acl <no-dsa> (Will be fixed first in unstable, then point release update; not to be backported by individual patches)
[bookworm] - acl <postponed> (Minor issue; local TOCTOU in recursive setfacl/chacl; fix needs 2.4.0 acl_*_at() ABI + walk_tree rewrite, not individually backportable)
[bullseye] - acl <postponed> (Minor issue; local TOCTOU in recursive setfacl/chacl; fix needs 2.4.0 acl_*_at() ABI + walk_tree rewrite, not individually backportable)
https://www.openwall.com/lists/oss-security/2026/06/29/1
Fixed by: https://cgit.git.savannah.nongnu.org/cgit/acl.git/commit/?id=601cc884a548ae9e9d246ae749e54b3272e4b1d7 (v2.4.0)
Fixed by: https://cgit.git.savannah.nongnu.org/cgit/acl.git/commit/?id=54e14e9bc545f505b379d0792a2748d9baf88700 (v2.4.0)
Fixed by: https://cgit.git.savannah.nongnu.org/cgit/acl.git/commit/?id=2c03ceefa0610d551d9cc089ce0a404cbe2d34b4 (v2.4.0)
Fixed by: https://cgit.git.savannah.nongnu.org/cgit/acl.git/commit/?id=2ee940139e9bba5005a3d987a6daecdda909089e (v2.4.0)
The fixes are based on a complete rewrite of the walk_tree helper.