[NEW] [medium] expat: Vulnerability allows unspecified attack

CSIRTS triage

What

A vulnerability in expat allows an unspecified attack vector.

Who is affected

Deployments using the expat library, particularly on local systems.

Urgency

Medium priority as exploitation requires local access and attack vector is unspecified.

Action

Check for and apply available security patches for expat CVE-2026-76957.

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

2026-08-20

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-2026-2930

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-2026-769570.10% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 1% of all EPSS-scored CVEs.

Referenced CVEs

Same CVEs, other sources

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

• mediumCVE-2026-76957: libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, …nvd
• mediumCVE-2026-76957: libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, …msrc

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