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

Published · last modified .

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.

EPSS exploit prediction

EPSS: 0.002 (10.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 11th percentile — 10.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-25210: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

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.