libexpat: Denial of service via XML entity amplification (CVE-2026-115506)
libexpat through 2.9.0 is vulnerable to a denial of service attack because the billion laughs protection in accountingDiffTolerated() detects entity amplification too late.
CVE search metadata
CVE search record: CVE-2026-115506. Severity: high. CVSS: 7.5. KEV: no. Product: libexpat (<= 2.9.0). Brief: libexpat: Denial of service via XML entity amplification (CVE-2026-115506). Brief link: https://feed.craftedsignal.io/briefs/2026-10-libexpat-dos/
Triage facts
Revision 1- Applicability
- libexpat (<= 2.9.0)
- Evidence
- Unknown
- Severity
- Low
- Sources
- 1 public source
- Freshness
- Revision 1Oct 23, 07:36 UTC
- Vulnerabilities
- 1 CVE
- Source quality
- A2Roughly even chance
libexpat through 2.9.0 contains a denial of service vulnerability because the billion laughs protection in accountingDiffTolerated() within xmlparse.c detects entity amplification too late. Attackers can supply a moderately sized XML document with a large DTD and nested entity expansions to consume tens of seconds of CPU per parse.