CVE-2026-18508

CVE Details

Release Date:	2026-08-03
Impact:	Moderate	What is this?

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.

See more information about CVE-2026-18508 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	4.4
Vector String:	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Version:	3.1
Attack Vector:	Local
Attack Complexity:	Low
Privileges Required:	None
User Interaction:	Required
Scope:	Unchanged
Confidentiality Impact:	Low
Integrity Impact:	Low
Availability Impact:	None

Errata information

Platform	Errata	Release Date
Oracle Linux version 9 (tar)	ELSA-2026-61581-0	2026-09-01