Description
libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.
Affected products
libexpat_project: libexpat
References3
- github.com/libexpat/libexpat/pull/1322 Issue TrackingPatchVendor Advisory
- github.com/libexpat/libexpat/pull/1329 Issue TrackingPatch
- cert-portal.siemens.com/productcert/html/ssa-457936.html
Metrics
- CVSS 3.1
-
7.8
HIGH
Score source: NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 1 · as of 10 November 2026
- CWE
- CWE-416
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