CVE-2026-18477

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account, but needs a user to act. High risk of data tampering.

Exploit odds

0.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-08-03 17:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-11-05 20:17 UTC Last updatedMost recent change to the record

Details

Published

2026-08-03 17:16 UTC

Last modified

2026-11-05 20:17 UTC

Exploit probability

0.1% · EPSS, next 30 days

Weakness

CWE-367

Record status

Modified

Affected

• Gnu Tar 1.35
• Redhat Openshift Container Platform 4.0
• Redhat Enterprise Linux 8.0
• Redhat Enterprise Linux 9.0
• Redhat Enterprise Linux 10.0

Attack profile CVSS 3.1 · 4.4

Attack vector

Local

Complexity

High

Privileges needed

Low

User interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None