[NEW] [UNPATCHED] [medium] GNU tar: Multiple vulnerabilities enable file manipulation

mediumCVE-2026-18477 CVE-2026-18508

An attacker can exploit multiple vulnerabilities in GNU tar to manipulate files.

CSIRTS triage

vendor: GNU product: tar Path traversal

What: Multiple vulnerabilities enable attackers to manipulate files during extraction.
Who is affected: Systems using GNU tar, particularly when extracting untrusted archives.
Urgency: Medium severity with no patch available; prioritize workarounds or alternative tools.
Action: Avoid extracting untrusted tar archives or implement input validation; monitor for patches.

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: 2026-08-04
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-2026-2633

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-2026-184770.10% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 1% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-185080.13% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 3% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-18477	coverage & exploitation status	NVD · CVE.org
CVE-2026-18508	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

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.

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
medium[UPDATE] [medium] GNU tar: Vulnerability allows bypassing of security measurescert-bund · 2026-07-23
mediumCVE-2026-53655: node-tar applies PAX size override to intermediary GNU long-name/long-link headers, causing ta…msrc · 2026-06-09