CVE-2026-115506: high-severity vulnerability in libexpat
libexpat through 2.9.0 Denial of Service via Billion Laughs Detection Delay
Published · Updated
41Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 8.7epss 0.5%
exploitation probability
0.5%top 61% of all CVEs
observed exploitation
nono source reports it
1 public exploit(s)
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.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Affected products
libexpat · libexpatpublic PoCs found — 1
cve_referencegithub.com/hannob/lolololunverified⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
Related CVEs — libexpat
In the same product, most dangerous first.
CVE-2026-113351HIGHlibexpat 2.7.2 through 2.9.0 Denial of Service via XML_ParserResetEPSS 0.5%CVE-2026-118370HIGHlibexpat through 2.9.0 Integer Overflow in storeAtts via attIndex and nPrefixesEPSS 0.4%CVE-2026-117610HIGHlibexpat through 2.9.0 NULL Pointer Dereference via External Entity SubparserEPSS 0.4%CVE-2026-93990HIGHExpat before 2.8.5 Malformed UTF-16 Acceptance via Unchecked SurrogateEPSS 0.4%CVE-2026-102633HIGHlibexpat 2.7.2 through 2.8.5 Integer Overflow in expat_reallocEPSS 0.4%CVE-2026-76641HIGHExpat Out-of-Bounds Read via dtdCopyEPSS 0.4%