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OpenAdvisories
High ALAS2023-2026-1986 2 CVEs

Important: acl security update (Amazon Linux 2023)

Published Jul 20, 2026 · Updated Jul 20, 2026

Summary

Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-2026-54370: A time-of-check to time-of-use (TOCTOU) race condition vulnerability was found in acl. By replacing a pathname component with a symbolic link between a security check and subsequent file operations, an attacker can redirect file access control list operations. This occurs when privileged processes invoke `getfacl` or `setfacl` over an attacker-controlled path, potentially leading to local privilege escalation. CVE-2026-54369: A flaw was found in the `acl` component, specifically within its `libacl` pathname-based functions. A local attacker could exploit this vulnerability by using a symbolic link to replace a pathname component. This could allow the attacker to redirect access control list (ACL) read or write operations to arbitrary files or directories, leading to unauthorized manipulation of ACLs and ultimately local privilege escalation.

Fixed packages 6

ReleasePackageFixed in
Amazon Linux · 2023 acl 0:2.4.0-1.amzn2023.0.1
Amazon Linux · 2023 acl-debuginfo 0:2.4.0-1.amzn2023.0.1
Amazon Linux · 2023 acl-debugsource 0:2.4.0-1.amzn2023.0.1
Amazon Linux · 2023 libacl 0:2.4.0-1.amzn2023.0.1
Amazon Linux · 2023 libacl-debuginfo 0:2.4.0-1.amzn2023.0.1
Amazon Linux · 2023 libacl-devel 0:2.4.0-1.amzn2023.0.1

Vulnerabilities 2

  • High 7.1

    acl < 2.4.0 Symlink Traversal Privilege Escalation via libacl Functions

    acl before version 2.4.0 contains a symlink traversal vulnerability in the libacl pathname-based functions acl_get_file(), acl_set_file(), acl_extended_file(), and acl_delete_def_file() that allows local attackers to escalate privileges by replacing any pathn…

  • Medium 6.3

    acl < 2.4.0 TOCTOU Symlink Traversal via getfacl/setfacl/chacl

    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-fo…

References

  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-54369.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-54370.html