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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| acl project | acl | < 2.4.0 | 2.4.0 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | acl | 2.4.0-1 | — |
| Debian 13 | acl | No fix yet | — |
| Debian 12 | acl | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | acl | No fix yet | — |
| Ubuntu 25.10 | acl | No fix yet | — |
| Ubuntu 24.04 LTS | acl | No fix yet | — |
| Ubuntu 22.04 LTS | acl | No fix yet | — |
| Ubuntu 20.04 LTS | acl | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | acl | No fix yet | — |
| Ubuntu 16.04 LTS | acl | No fix yet | — |
| Ubuntu 14.04 LTS | acl | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | acl +2 | 2.4.0-1.el10_2 | RHSA-2026:42739 |
| RHEL 9 | acl +2 | 2.4.0-1.el9_8 | RHSA-2026:42736 |
| RHEL 8 | acl +2 | 2.4.0-1.el8_10 | RHSA-2026:43420 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 ELS | acl | 2.4.0-0.el7_9.1 | RHSA-2026:98129 |
| Red Hat Hardened Images 1 | acl +2 | 2.4.0-0.1.hum1 | RHSA-2026:34351 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | acl +2 | 2.4.0-1.el10_2 | ALSA-2026:42739 |
| AlmaLinux 9 | acl +2 | 2.4.0-1.el9_8 | ALSA-2026:42736 |
| AlmaLinux 8 | acl +2 | 2.4.0-1.el8_10 | ALSA-2026:43420 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | acl | 2.4.0-1.el10_2 | RLSA-2026:42739 |
| Rocky Linux 9 | acl | 2.4.0-1.el9_8 | RLSA-2026:42736 |
| Rocky Linux 8 | acl | 2.4.0-1.el8_10 | RLSA-2026:43420 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | acl | 2.4.0-150000.4.6.1 | SUSE-SU-2026:4176-1 |
| SLES 15 SP7 | attr | 2.6.0-150000.4.3.1 | SUSE-SU-2026:4176-1 |
| SLES 15 SP6 | acl | 2.4.0-150000.4.6.1 | SUSE-SU-2026:4176-1 |
| SLES 15 SP6 | attr | 2.6.0-150000.4.3.1 | SUSE-SU-2026:4176-1 |
| SLES 15 SP5 | acl | 2.4.0-150000.4.6.1 | SUSE-SU-2026:4176-1 |
| SLES 15 SP5 | attr | 2.6.0-150000.4.3.1 | SUSE-SU-2026:4176-1 |
| SLES 15 SP4 | acl | 2.4.0-150000.4.6.1 | SUSE-SU-2026:4176-1 |
| SLES 15 SP4 | attr | 2.6.0-150000.4.3.1 | SUSE-SU-2026:4176-1 |
Show 11 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | acl | 2.4.0-160000.1.1 | SUSE-SU-2026:23726-1, SUSE-SU-2026:23705-1 |
| SLES for SAP 16.0 | attr | 2.6.0-160000.1.1 | SUSE-SU-2026:23726-1, SUSE-SU-2026:23705-1 |
| SLES for SAP 15 SP6 | acl | 2.4.0-150000.4.6.1 | SUSE-SU-2026:4176-1 |
| SLES for SAP 15 SP6 | attr | 2.6.0-150000.4.3.1 | SUSE-SU-2026:4176-1 |
| SLES for SAP 15 SP5 | acl | 2.4.0-150000.4.6.1 | SUSE-SU-2026:4176-1 |
| SLES for SAP 15 SP5 | attr | 2.6.0-150000.4.3.1 | SUSE-SU-2026:4176-1 |
| SLES for SAP 15 SP4 | acl | 2.4.0-150000.4.6.1 | SUSE-SU-2026:4176-1 |
| SLES for SAP 15 SP4 | attr | 2.6.0-150000.4.3.1 | SUSE-SU-2026:4176-1 |
| SLES 16.0 | acl | 2.4.0-160000.1.1 | SUSE-SU-2026:23726-1, SUSE-SU-2026:23705-1 |
| SLES 16.0 | attr | 2.6.0-160000.1.1 | SUSE-SU-2026:23726-1, SUSE-SU-2026:23705-1 |
| SLE Micro 6.2 | acl | 2.4.0-160000.1.1 | SUSE-SU-2026:23670-1 |
| SLE Micro 6.2 | attr | 2.6.0-160000.1.1 | SUSE-SU-2026:23670-1 |
| SLE Micro 5.5 | acl | 2.4.0-150000.4.6.1 | SUSE-SU-2026:4176-1 |
| SLE Micro 5.5 | attr | 2.6.0-150000.4.3.1 | SUSE-SU-2026:4176-1 |
| SLE Micro 5.4 | acl | 2.4.0-150000.4.6.1 | SUSE-SU-2026:4176-1 |
| SLE Micro 5.4 | attr | 2.6.0-150000.4.3.1 | SUSE-SU-2026:4176-1 |
| SLE Micro 5.3 | acl | 2.4.0-150000.4.6.1 | SUSE-SU-2026:4176-1 |
| SLE Micro 5.3 | attr | 2.6.0-150000.4.3.1 | SUSE-SU-2026:4176-1 |
| SLE HPC 15 SP5 | acl | 2.4.0-150000.4.6.1 | SUSE-SU-2026:4176-1 |
| SLE HPC 15 SP5 | attr | 2.6.0-150000.4.3.1 | SUSE-SU-2026:4176-1 |
| SLE HPC 15 SP4 | acl | 2.4.0-150000.4.6.1 | SUSE-SU-2026:4176-1 |
| SLE HPC 15 SP4 | attr | 2.6.0-150000.4.3.1 | SUSE-SU-2026:4176-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | acl | 2.4.0-1.1 | openSUSE-SU-2026:11312-1 |
| openSUSE Leap 16.0 | acl | 2.4.0-160000.1.1 | openSUSE-SU-2026:21832-1 |
| openSUSE Leap 16.0 | attr | 2.6.0-160000.1.1 | openSUSE-SU-2026:21832-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | acl +2 | 2.4.0-1.amzn2023.0.1 | ALAS2023-2026-1986 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | acl | 2.4.0-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | acl +2 | 2.4.0-1.el10_2 | ELSA-2026-42739 |
| Oracle Linux 9 | acl +2 | 2.4.0-1.el9_8 | ELSA-2026-42736 |
| Oracle Linux 8 | acl +2 | 2.4.0-1.el8_10 | ELSA-2026-43420 |
Advisories 24
- RHSA-2026:98129 Red Hat Security Advisory: acl security update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- WID-SEC-2026-2453 Red Hat Enterprise Linux (acl): Mehrere Schwachstellen ermöglichen Privilegieneskalation und Manipulation von Dateien BSI CERT-Bund (WID) · Nov 10, 2026
- ALSA-2026:42736 Important: acl security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:42739 Important: acl security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:43420 Important: acl security update AlmaLinux Security Advisories · Oct 29, 2026
- WID-SEC-2026-2919 IBM App Connect Enterprise: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 27, 2026
- RHSA-2026:43420 Red Hat Security Advisory: acl security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:42736 Red Hat Security Advisory: acl security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:42739 Red Hat Security Advisory: acl security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:34351 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- SUSE-SU-2026:23705-1 Security update for acl, attr SUSE / openSUSE Security Updates · Sep 29, 2026
- SUSE-SU-2026:23726-1 Security update for acl, attr SUSE / openSUSE Security Updates · Sep 29, 2026
- SUSE-SU-2026:23670-1 Security update for acl, attr SUSE / openSUSE Security Updates · Sep 29, 2026
- WID-SEC-2026-3043 IBM QRadar SIEM: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 17, 2026
- SUSE-SU-2026:4176-1 Security update for acl, attr SUSE / openSUSE Security Updates · Sep 15, 2026
- openSUSE-SU-2026:21832-1 Security update for acl, attr SUSE / openSUSE Security Updates · Sep 13, 2026
- RLSA-2026:43420 Important: acl security update Rocky Linux Security Advisories · Jul 23, 2026
- RLSA-2026:42736 Important: acl security update Rocky Linux Security Advisories · Jul 22, 2026
- RLSA-2026:42739 Important: acl security update Rocky Linux Security Advisories · Jul 22, 2026
- ELSA-2026-43420 Important: acl security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jul 22, 2026
- openSUSE-SU-2026:11312-1 acl-2.4.0-1.1 on GA media SUSE / openSUSE Security Updates · Jul 21, 2026
- ELSA-2026-42739 Important: acl security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Jul 21, 2026
- ELSA-2026-42736 Important: acl security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jul 21, 2026
- ALAS2023-2026-1986 Important: acl security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Jul 20, 2026
References
- https://cgit.git.savannah.nongnu.org/cgit/acl.git/commit/?id=3589787cd589b34bdd9265936e17190b6d3f17d1 patch
- https://cgit.git.savannah.nongnu.org/cgit/acl.git/commit/?id=24a227d0ab8576612194f8a56c2314389adc74a5 issue-tracking
- https://www.vulncheck.com/advisories/acl-toctou-symlink-traversal-via-getfacl-setfacl-chacl third-party-advisory