CVE catalog
CVE-2026-54370
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 symbo
- Severity
- High · CVSS 7.4
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.09% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | acl | sid | 2.4.0-1 | fixed |
| Debian | acl | forky | 2.4.0-1 | fixed |
| Debian | acl | trixie | 2.3.2-2 | vulnerable |
| Debian | acl | bookworm | 2.3.1-3 | vulnerable |
| Cpe | acl | Not reported | Not reported | vulnerable |
| Ubuntu | acl | 14.04 | 2.2.52-1 | vulnerable |
| Ubuntu | acl | 16.04 | 2.2.52-2 | vulnerable |
| Ubuntu | acl | 16.04 | 2.2.52-3 | vulnerable |
| Ubuntu | acl | 18.04 | 2.2.52-3build1 | vulnerable |
| Ubuntu | acl | 20.04 | 2.2.53-4 | vulnerable |
| Ubuntu | acl | 20.04 | 2.2.53-5 | vulnerable |
| Ubuntu | acl | 20.04 | 2.2.53-5ubuntu1 | vulnerable |
| Ubuntu | acl | 20.04 | 2.2.53-6 | vulnerable |
| Ubuntu | acl | 22.04 | 2.2.53-10ubuntu2 | vulnerable |
| Ubuntu | acl | 22.04 | 2.3.1-1 | vulnerable |
| Ubuntu | acl | 24.04 | 2.3.1-3 | vulnerable |
| Ubuntu | acl | 24.04 | 2.3.1-4ubuntu1 | vulnerable |
| Ubuntu | acl | 24.04 | 2.3.2-1 | vulnerable |
| Ubuntu | acl | 24.04 | 2.3.2-1build1 | vulnerable |
| Ubuntu | acl | 24.04 | 2.3.2-1build1.1 | vulnerable |
| Ubuntu | acl | 25.10 | 2.3.2-2 | vulnerable |
| Ubuntu | acl | 26.04 | 2.3.2-2 | vulnerable |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | acl | source | sid | 2.4.0-1 | not yet assigned | Not reported | [1141110] |
| Debian | acl | source | forky | 2.4.0-1 | not yet assigned | Not reported | [1141110] |
| Debian | acl | source | trixie | (unfixed) | not yet assigned | Not reported | [1141110] |
| Debian | acl | source | bookworm | (unfixed) | not yet assigned | Not reported | [1141110] |
Notes
[trixie] acl: Will be fixed first in unstable, then point release update; not to be backported by individual patches [bookworm] acl: Minor issue; local TOCTOU in recursive setfacl/chacl; fix needs 2.4.0 acl_*_at() ABI + walk_tree rewrite, not individually backportable
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [acl]Affected
Details (2)
2.3.1-3· amd64 · bookwormAffected
nvd · acl · debian · bookworm; nvd · acl · debian · 12
2.3.1-3· arm64 · bookwormAffected
nvd · acl · debian · bookworm; nvd · acl · debian · 12
- [libacl1]Affected
Source package: [acl]
Details (2)
2.3.1-3· amd64 · bookwormAffected
nvd · acl · debian · bookworm; nvd · acl · debian · 12
2.3.1-3· arm64 · bookwormAffected
nvd · acl · debian · bookworm; nvd · acl · debian · 12
- [libacl1-dev]Affected
Source package: [acl]
Details (2)
2.3.1-3· amd64 · bookwormAffected
nvd · acl · debian · bookworm; nvd · acl · debian · 12
2.3.1-3· arm64 · bookwormAffected
nvd · acl · debian · bookworm; nvd · acl · debian · 12
[Debian 13 (Trixie)]
- [acl]Affected
Source package: [acl]
Details (2)
2.3.2-2+b1· amd64 · trixieAffected
nvd · acl · debian · 13
2.3.2-2+b1· arm64 · trixieAffected
nvd · acl · debian · 13
- [libacl1]Affected
Source package: [acl]
Details (2)
2.3.2-2+b1· amd64 · trixieAffected
nvd · acl · debian · 13
2.3.2-2+b1· arm64 · trixieAffected
nvd · acl · debian · 13
- [libacl1-dev]Affected
Source package: [acl]
Details (2)
2.3.2-2+b1· amd64 · trixieAffected
nvd · acl · debian · 13
2.3.2-2+b1· arm64 · trixieAffected
nvd · acl · debian · 13
Observed:
References
- [https://cgit.git.savannah.nongnu.org/cgit/acl.git/commit/?id=24a227d0ab8576612194f8a56c2314389adc74a5]
- [https://cgit.git.savannah.nongnu.org/cgit/acl.git/commit/?id=3589787cd589b34bdd9265936e17190b6d3f17d1]
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_11312-1.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-54370]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-54370]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-54370]
- [https://security-tracker.debian.org/tracker/CVE-2026-54370]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-54370.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2919.json]
- [https://www.vulncheck.com/advisories/acl-toctou-symlink-traversal-via-getfacl-setfacl-chacl]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]