[UPDATE] [medium] GNU tar: Vulnerability allows bypassing of security measures

mediumCVE-2026-5704

A local attacker can exploit a vulnerability in GNU tar to bypass security measures.

CSIRTS triage

vendor: GNU product: tar Authentication bypass

What: A local attacker can exploit a vulnerability in GNU tar to bypass security measures.
Who is affected: Local deployments of GNU tar.
Urgency: Remediation is medium urgency due to the potential for security measure bypass.
Action: Update to the latest version of GNU tar.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: CERT-Bund (BSI) Security Advisories (DE · national-cert · site)
Severity: medium
Published: 2026-07-23
Exploitation: Not in CISA KEV at last sync
Language: Machine-translated to English — verify against the original

Original advisory: https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-1057

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-57040.37% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 31% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-5704	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

unknownUSN-8477-3: tar regressionubuntu
unknownUSN-8477-2: tar regressionubuntu

Recent advisories for GNU tar

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

medium[NEW] [UNPATCHED] [medium] GNU tar: Multiple vulnerabilities enable file manipulationcert-bund · 2026-08-10
unknownCVE-2026-66484: GNU cpio contains a Path Traversal vulnerability in its tar archive extraction functionality. …nvd · 2026-08-10
mediumCVE-2025-45582: GNU Tar through 1.35 allows file overwrite via directory traversal in crafted TAR archives, wi…msrc · 2026-08-06
mediumCVE-2026-18477: A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename…nvd · 2026-08-03
mediumCVE-2026-18508: A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardl…nvd · 2026-08-03
mediumCVE-2026-53655: node-tar applies PAX size override to intermediary GNU long-name/long-link headers, causing ta…msrc · 2026-06-09