CVE-2026-18477Tar: tar: toctou in incremental dumpdir 'x' rename handling allows restore path escape

Description

A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling allows a local attacker with write access to a directory being backed up to influence the restore process if the attacker has access to the system where the restore is being performed. During restoration, files or directories may be created, renamed or overwritten outside the intended extraction directory. This could lead to unauthorized file modification or, in some cases, privilege escalation. Exploitation does not require the attacker to modify or craft the archive, and standard backup and restore workflows—including extracting into a newly created directory without using the -P option do not mitigate the issue.

Timeline

Scores

EPSS (exploitation in 30 days)

0.10% · top 99% of all CVEs (14 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.4.

Affected products

• Red Hat · Red Hat Enterprise Linux 10

  • unaffected 2:1.35-13.el10_2 – < *

• Red Hat · Red Hat Enterprise Linux 8

  • unaffected 2:1.30-13.el8_10 – < *

• Red Hat · Red Hat Enterprise Linux 9

  • unaffected 2:1.34-13.el9_8 – < *

• Red Hat · Red Hat Discovery 2

  • unaffected 1788205779 – < *

• Red Hat · Red Hat Hardened Images

  • unaffected 1.35-9.1.hum1 – < *

• Red Hat · Red Hat Update Infrastructure 5

  • unaffected 1788880445 – < *

• Red Hat · Red Hat Update Infrastructure 5

  • unaffected 1788880464 – < *

• Red Hat · Red Hat Update Infrastructure 5

  • unaffected 1788880456 – < *

• Red Hat · Red Hat Update Infrastructure 5

  • unaffected 1788765051 – < *

• Red Hat · Red Hat Update Infrastructure 5

  • unaffected 1788880581 – < *

• Red Hat · Red Hat Enterprise Linux 6

  All versions: unknown

• Red Hat · Red Hat Enterprise Linux 7

  All versions: unknown

• Red Hat · Red Hat Hardened Images

  All versions: unaffected

• Red Hat · Red Hat Hardened Images

  All versions: unaffected

• Red Hat · Red Hat Hardened Images

  All versions: unaffected

• Red Hat · Red Hat Hardened Images

  All versions: unaffected

• Red Hat · Red Hat Hardened Images

  All versions: unaffected

• Red Hat · Red Hat Hardened Images

  All versions: unaffected

• Red Hat · Red Hat Hardened Images

  All versions: unaffected

• Red Hat · Red Hat Hardened Images

  All versions: unaffected

• Red Hat · Red Hat Hardened Images

  All versions: unaffected

• Red Hat · Red Hat Hardened Images

  All versions: unaffected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 5

  All versions: affected

What to do

Workaround: Do not perform incremental restores (-G/-g) from untrusted archives. Avoid restoring incremental backups on systems where untrusted users have shell access,​ perform restoration only on systems inaccessible to users.

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-52336 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-18477](https://cveledger.app/badge/CVE-2026-18477.svg)](https://cveledger.app/cve/CVE-2026-18477)

Record last updated 5 Nov 2026, 19:25 UTC.