CVE-2026-115506
libexpat through 2.9.0 Denial of Service via Billion Laughs Detection Delay
libexpat libexpatLibraries & packages
CVSS
8.7HighExploitationPublic exploit codeCISA's assessment says proof of concept code is public, assessed 23 Oct 2026. Not in the KEV catalogCISA via CVE List
Exploit odds (EPSS)0.35%Chance of exploitation activity in the next 30 days, higher than 27% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
What fixes it
No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.
Description
libexpat through 2.9.0 contains a denial of service vulnerability because billion laughs protection in accountingDiffTolerated() in 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.
Text from CVE List
Affected versions 1
- libexpataffected: all versions through 2.9.0CVE List
References 5
- github.com/libexpat/libexpat/pull/1433Fixvia CVE List
- vulncheck.com/advisories/libexpat-through-2.9.0-denial-of-service-via-billion-laughs-detection-delayAdvisoryvia CVE List
- github.com/hannob/lolololExploitvia CVE List
- github.com/libexpat/libexpat/issues/1160Referencevia CVE List
- github.com/libexpat/libexpatReferencevia CVE List