CVE-2026-102633highCWE-190

CVE-2026-102633: high-severity vulnerability in libexpat

libexpat 2.7.2 through 2.8.5 Integer Overflow in expat_realloc

Published

21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 8.2epss 0.3%
exploitation probability
0.3%top 74% of all CVEs
observed exploitation
nono source reports it
libexpat versions 2.7.2 through 2.8.5 contain an integer overflow vulnerability in expat_realloc() function on 32-bit platforms when computing allocation sizes. Attackers supplying malicious XML to applications parsing with vulnerable libexpat can cause heap buffer overflow, memory corruption, or denial of service.
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Affected products
libexpat · libexpat
Related CVEs — libexpat

In the same product, most dangerous first.

CVE-2026-93990HIGHExpat before 2.8.5 Malformed UTF-16 Acceptance via Unchecked SurrogateEPSS 0.4%CVE-2026-76641HIGHExpat Out-of-Bounds Read via dtdCopyEPSS 0.4%CVE-2026-77214HIGHlibexpat Heap Buffer Over-read in xmlparse.c via XML_ParseBufferEPSS —
References
https://github.com/libexpat/libexpathttps://github.com/libexpat/libexpat/blob/R_2_8_5/expat/lib/xmlparse.c#L1003https://github.com/libexpat/libexpat/commit/209801d7fbaf07ab74bae8cb32dd2ab9e5846118https://github.com/libexpat/libexpat/pull/1392https://www.vulncheck.com/advisories/libexpat-2.7.2-through-2.8.5-integer-overflow-in-expat-realloc