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Vulnerability record · CVE-2026-54370 · published 29 June 2026

CVE-2026-54370: TOCTOU race condition vulnerability

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.

7.2 CVSS 4.0 High EPSS 0.11% · top 98.8% CWE-367 · TOCTOU race condition Deferred
7.2CVSS 4.0 base score
0.11%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
3References
29 Jun 2026Last modified by NVD

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.

CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

References

LinkTags
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://www.vulncheck.com/advisories/acl-toctou-symlink-traversal-via-getfacl-setfacl-chacl

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-54370), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.