CVE-2026-18508

Tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file overwrite

MEDIUM
4.4
CVSS Score
Published: August 3, 2026 at 02:51 PM UTC
Updated: September 22, 2026 at 10:17 PM UTC
3 products affected across 2 vendorsEnterprise LinuxOpenShift Container PlatformTar

Using Red Hat Enterprise Linux 10 by Red Hat?

Get instant alerts when new vulnerabilities affect Red Hat Enterprise Linux 10 - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM4.4
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Vendor states this is fixed in 2:1.30-13.el8_10 (unaffected)
Vendor states this is fixed in 2:1.34-13.el9_8 (unaffected)
Vendor states this is fixed in 2:1.35-13.el10_2 (unaffected)
Vendor states this is fixed in 6 (unknown)
Vendor states this is fixed in 7 (unknown)

References (8)

VDB Entryx_refsource_REDHATVendor Advisory
Source: cverecord
https://access.redhat.com/security/cve/CVE-2026-18508
Issue Trackingx_refsource_REDHATVendor Advisory
Source: cverecord
https://bugzilla.redhat.com/show_bug.cgi?id=2509843
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:50807
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:61581
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:61783
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:61586
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:66018
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:70390

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.4MEDIUMredhat
Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-59

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card