CVE-2026-18477

MEDIUM

MEDIUM Priority: 0.00 BB Relevance: 14/100

Published: 2026-08-03 Modified: 2026-10-30 First seen: 2026-10-30 Status: active

Attack Surface

Integ. Impact

CVSS Vector Breakdown

AV: Local

AC: High

PR: Low

UI: Required

S: Unchanged

C: None

I: High

A: None

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.

Weakness Classification (1)

CWE-367 — Time-of-check Time-of-use (TOCTOU) Race Condition