[NEW] [medium] expat: Vulnerability enables denial of service

CSIRTS triage

What

A vulnerability in expat allows local attackers to conduct denial of service attacks.

Who is affected

Systems running expat that allow local attacker access.

Urgency

Medium—local attack only; denial of service risk.

Action

Update expat to a patched version.

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

Details

Source

CERT-Bund (BSI) Security Advisories (DE · national-cert · site)

Severity

medium

Published

2026-08-18

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-2026-2718

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-2026-725220.18% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 7% of all EPSS-scored CVEs.

Referenced CVEs

Same CVEs, other sources

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

• highDSA-6446-1 expat - security updatedebian
• mediumCVE-2026-72522: libexpat before 2.8.3 has an out-of-bounds read and resultant infinite loop because low surrog…msrc
• mediumCVE-2026-72522: libexpat before 2.8.3 has an out-of-bounds read and resultant infinite loop because low surrog…nvd

Recent advisories for expat

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] expat: Vulnerability Enables Denial of Servicecert-bund · 2026-08-19
• highCVE-2026-66046: Expat through 2.8.3 contains a denial of service vulnerability caused by quadratic algorithmic…nvd · 2026-08-18
• highDSA-6446-1 expat - security updatedebian · 2026-08-18
• low[UPDATE] [low] expat: Vulnerability allows Denial of Servicecert-bund · 2026-08-06
• unknownDSA-6404-1 expat - security updatedebian · 2026-07-30
• medium[UPDATE] [medium] expat: Multiple vulnerabilitiescert-bund · 2026-07-22

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