Vulnerability in Libexpat
CVE-2026-113351
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.
Published .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/libexpat/libexpat/pull/1431 (issue-tracking, patch)
- github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expa… (technical-description)
- github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expa… (technical-description)
- github.com/libexpat/libexpat (product)
- VulnCheck Advisory: libexpat 2.7.2 through 2.9.0 Denial of Service via XML_ParserReset (third-party-advisory)
Frequently asked questions
- What is CVE-2026-113351?
- CVE-2026-113351 is a medium-severity vulnerability in Libexpat, classified under CWE-909. CVSS score: 5.9/10. Published 2026-10-20.
- How severe is CVE-2026-113351?
- Medium severity. CVSS v3 base score is 5.9 out of 10.