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MEDIUM

CVE-2026-18508

CVSS v3

4.4

MEDIUM

EPSS Score

0.1 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • tarAlmaLinux:10all versions · fixed in 2:1.35-13.el10_2
  • tarAlmaLinux:9all versions · fixed in 2:1.34-13.el9_8
  • tarAlmaLinux:8all versions · fixed in 2:1.30-13.el8_10

Vendor advisories

  • CVE-2026-18508 Red Hat Product Security49 products fixed · 4 known affected

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

    tar.src as a component of Red Hat Enterprise Linux 6 · tar.src as a component of Red Hat Enterprise Linux 7 · openshift/ose-rhel-coreos-8 as a component of Red Hat OpenShift Container Platform 4

  • RHSA-2026:70390 Red Hat Product Security13 products fixed

    Red Hat Security Advisory: tar security, bug fix, and enhancement update

  • RHSA-2026:66018 Red Hat Product Security5 products fixed

    Red Hat Security Advisory: Red Hat Update Infrastructure 5.3 security update

  • RHSA-2026:61586 Red Hat Product Security13 products fixed

    Red Hat Security Advisory: tar security, bug fix, and enhancement update

  • RHSA-2026:61783 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: A Subscription Management tool for finding and reporting Red Hat product usage

  • RHSA-2026:61581 Red Hat Product Security13 products fixed

    Red Hat Security Advisory: tar security, bug fix, and enhancement update

1 more advisory

Full record on NVD

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Published
2026-08-03
Last Modified
2026-08-03

Frequently asked questions

What is 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.

Is CVE-2026-18508 actively exploited?

Active exploitation of CVE-2026-18508 has not been confirmed. Its EPSS score was 0.1% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-18508?

CVE-2026-18508 has a CVSS v3 base score of 4.4 (MEDIUM severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.

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