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.
Published: 2026-08-03
Score: 4.4 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

Vendor Workaround

Avoid restoring incremental backups on systems where untrusted users have shell access, particularly if they could have modified or controlled any of the backed-up data. When restoring backups containing user-controlled content, perform the restoration only on systems that are inaccessible to those users.

Tracking

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Advisories

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History

Mon, 03 Aug 2026 16:30:00 +0000

Type Values Removed Values Added
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.
Title Tar: tar: toctou in incremental dumpdir 'x' rename handling allows restore path escape
First Time appeared Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
Weaknesses CWE-367
CPEs cpe:/a:redhat:hummingbird:1
cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
References
Metrics cvssV3_1

{'score': 4.4, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N'}


Subscriptions

Redhat Enterprise Linux Hummingbird Openshift
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-08-03T16:26:49.498Z

Reserved: 2026-07-31T10:48:40.556Z

Link: CVE-2026-18477

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses
  • CWE-367

    Time-of-check Time-of-use (TOCTOU) Race Condition