Vulnerability in GNU Tar
CVE-2026-18508
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.001 (3.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 3.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000
Affected products
- GNU Tar — versions 1.35
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat Hardened Images — versions 1.35-9.2.hum1
- Red Hat Openshift Container Platform 4
- Red Hat Openshift Container Platform 5
- Red Hat Enterprise Linux — versions 10.0, 8.0, 9.0
Weakness classification (CWE)
References
- access.redhat.com/security/cve/CVE-2026-18508 (vdb-entry, Vendor Advisory)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking, Issue Tracking, Vendor Advisory)
- access.redhat.com/errata/RHSA-2026:50807 (vendor-advisory, Vendor Advisory)
- access.redhat.com/errata/RHSA-2026:61581 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:61783 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:61586 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:66018 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:70390 (vendor-advisory)
Frequently asked questions
- What is CVE-2026-18508?
- CVE-2026-18508 is a medium-severity vulnerability in GNU Tar, classified under Improper Link Resolution Before File Access. CVSS score: 4.4/10. Published 2026-08-03.
- How severe is CVE-2026-18508?
- Medium severity. CVSS v3 base score is 4.4 out of 10.