What’s Vulnerable › Vulnerabilities

CVE-2026-113351: libexpat 2.7.2 through 2.9.0 Denial of Service via XML_ParserReset

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-20 · updated 2026-10-20
• Weakness: CWE-909

Description

libexpat 2.7.2 through 2.9.0 contains a denial of service vulnerability because XML_ParserReset zeroes the direct byte count but never offsets tracked heap allocations. Attackers can submit a large XML document so later documents on the same reset parser fail with XML_ERROR_NO_MEMORY until it is recreated.

Affected products

• libexpat: from 2.7.2 through 2.9.0

References

• https://github.com/libexpat/libexpat
• https://github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expat/lib/xmlparse.c#L1560
• https://github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expat/lib/xmlparse.c#L860-L884
• https://github.com/libexpat/libexpat/pull/1431
• https://www.vulncheck.com/advisories/libexpat-2.7.2-through-2.9.0-denial-of-service-via-xml-parserreset

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