CVE-2026-102633

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

8.2CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.4% chance of exploitation in the next 30 days; higher than 30% of CVEs (scores of 2026-10-25)

CWE

CWE-190

Published

2026-09-29

Modified

2026-09-29

Record from

the NVD, synced 2026-10-19

References

• https://github.com/libexpat/libexpat
• https://github.com/libexpat/libexpat/blob/R_2_8_5/expat/lib/xmlparse.c#L1003
• https://github.com/libexpat/libexpat/commit/209801d7fbaf07ab74bae8cb32dd2ab9e5846118
• https://github.com/libexpat/libexpat/pull/1392
• https://www.vulncheck.com/advisories/libexpat-2.7.2-through-2.8.5-integer-overflow-in-expat-realloc

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