A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.
CVE-2026-18508
CVSS base score
4.4 (v3.1)
Severity
MEDIUM
Attack vector
Local
Weakness
CWE-59
Last modified
October 30, 2026
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Affected products
gnu tar
redhat openshift container platform
redhat enterprise linux
References
- access.redhat.com Vendor Advisory
- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com Vendor Advisory
- bugzilla.redhat.com Issue Tracking, Vendor Advisory