Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-07-31T00:00:00 tar: tar: TOCTOU in incremental dumpdir 'X' rename handling allows restore path escape 4.4 CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N CWE-367

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.

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.

This issue affects GNU tar incremental backup and restore (-g/-G). A local attacker who can write to content included in an incremental backup, and who can also access the system where that backup is later restored, may cause the restore to create, rename, or overwrite paths outside the intended extraction directory via a TOCTOU race in dumpdir 'X' handling. The attacker does not need to craft or alter the archive, and extracting it into a fresh directory does not mitigate the issue. Red Hat is assessing impact for the tar package in supported products. Red Hat would like to thank Marcin Wyczechowski (AFINE Team) and Michał Majchrowicz (AFINE Team) for reporting this issue. 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. Red Hat Hardened Images 2026-08-01T00:00:00Z RHSA-2026:49361 tar-main-1.35-9.1.hum1 Red Hat Enterprise Linux 10 Affected tar Red Hat Enterprise Linux 6 Out of support scope tar Red Hat Enterprise Linux 7 Out of support scope tar Red Hat Enterprise Linux 8 Affected tar Red Hat Enterprise Linux 9 Affected tar Red Hat Hardened Images Not affected aardvark-dns Red Hat Hardened Images Not affected chunkah Red Hat Hardened Images Not affected grafana12.4 Red Hat Hardened Images Not affected grafana13.1 Red Hat Hardened Images Not affected netavark Red Hat Hardened Images Not affected nodejs26 Red Hat Hardened Images Not affected python-cryptography Red Hat Hardened Images Not affected rust Red Hat Hardened Images Not affected rust-rpm-sequoia Red Hat Hardened Images Not affected yarnpkg Red Hat OpenShift Container Platform 4 Fix deferred rhcos https://www.cve.org/CVERecord?id=CVE-2026-18477 https://nvd.nist.gov/vuln/detail/CVE-2026-18477