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.
https://www.cisa.gov/news-events/ics-advisories/icsa-26-188-05
https://www.cisa.gov/news-events/ics-advisories/icsa-26-155-04
https://github.com/libexpat/libexpat/pull/1075/commits/9c2d990389e6abe2e44527eeaa8b39f16fe859c7
https://github.com/libexpat/libexpat/pull/1075
https://cert-portal.siemens.com/productcert/html/ssa-253495.html
Source: Mitre, NVD
Published: 2026-01-30
Updated: 2026-06-02
Base Score: 6.8
Vector: CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C
Severity: Medium
Base Score: 7.8
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity: High
EPSS: 0.00005