Integer overflow in Libexpat Project

CVE-2026-25210

In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation.

Vulnerability class: Integer Overflow

EPSS: 0.000 (0.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.9 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-25210?
CVE-2026-25210 is a medium-severity vulnerability in Libexpat Project, classified under Integer Overflow or Wraparound. CVSS score: 6.9/10. Published 2026-01-30.
How severe is CVE-2026-25210?
Medium severity. CVSS v3 base score is 6.9 out of 10.