[UPDATE] [medium] libarchive: Vulnerability allows code execution

mediumCVE-2026-5121

A remote attacker can exploit a vulnerability in libarchive to execute arbitrary code.

CSIRTS triage

vendor: libarchive product: libarchive Remote code execution

What: A vulnerability allows code execution.
Who is affected: A remote attacker can exploit this vulnerability.
Urgency: Remediation is medium urgency as the severity is moderate.
Action: Patch libarchive to the latest version to address the vulnerability.

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: 2026-08-11
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-2026-0923

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.

Moderate exploitation riskCVE-2026-51211.1% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 62% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-5121	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

high[UPDATE] [high] IBM QRadar SIEM: Multiple vulnerabilitiescert-bund
criticalSiemens SIDIS Secured SmartPlugcisa
unknownNCSC-2026-0229 [1.00] [M/H] Vulnerabilities fixed in Siemens productsncsc-nl

Recent advisories for libarchive

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] [medium] libarchive: Vulnerability enables denial of servicecert-bund · 2026-08-24
mediumCVE-2026-63134: Malcolm is a network traffic analysis tool suite. Prior to version 26.07.0, `safe-extract.py` …nvd · 2026-08-11
medium[UPDATE] [medium] libarchive: Multiple vulnerabilities allow information disclosure and DoScert-bund · 2026-08-11
high[UPDATE] [high] libarchive: Vulnerability enables Denial of Service and potentially Code Executioncert-bund · 2026-08-11
lowCVE-2026-16517: Libarchive: libarchive: signed integer overflow in archive_write_zip_headermsrc · 2026-08-06
low[NEW] [low] libarchive: Vulnerability allows unspecified attackcert-bund · 2026-07-23