CVE-2026-18477: A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling allows a local…
CVE-2026-18477 · Severity: medium · CVSS 4.4 · Published 2026-08-03
A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling allows a local attacker with write access to a directory being backed up to influence the restore process if the attacker has access to the system where the restore is being performed. During restoration, files or directories may be created, renamed or overwritten outside the intended extraction directory. This could lead to unauthorized file modification or, in some cases, privilege escalation. Exploitation does not require the attacker to modify or craft the archive, and standard backup and restore workflows—including extracting into a newly created directory without using the -P option do not mitigate the issue.
No. Junglewise Threat Intelligence has no report of CVE-2026-18477 being exploited in the wild.
How severe is CVE-2026-18477?
Medium severity, with a CVSS score of 4.4, published 3 August 2026.
Which products and versions are affected?
Gnu Tar, Redhat Enterprise Linux, Redhat Openshift Container Platform. The advisory does not name versions.
Is there a fix for CVE-2026-18477?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
Am I affected by CVE-2026-18477?
Check whether you run Gnu Tar, Redhat Enterprise Linux or Redhat Openshift Container Platform. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.