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.

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Fixes

Solution

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Workaround

Do not use --one-top-level as the sole confinement mechanism when extracting untrusted archives. Prefer extracting as an unprivileged user into a freshly created empty directory after changing into that directory (mkdir and cd), avoid extracting as root from sensitive working directories such as /, and follow the GNU tar security guidance for untrusted archives.

History

Mon, 03 Aug 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 03 Aug 2026 15:30:00 +0000

Type Values Removed Values Added
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.
Title Tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file overwrite
First Time appeared Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
Weaknesses CWE-59
CPEs cpe:/a:redhat:hummingbird:1
cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
References
Metrics cvssV3_1

{'score': 4.4, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-08-03T16:06:11.931Z

Reserved: 2026-07-31T17:08:04.550Z

Link: CVE-2026-18508

cve-icon Vulnrichment

Updated: 2026-08-03T16:02:40.067Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses