CVE-2026-56412

Severity: medium (CVSS 5.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-21 · updated 2026-10-25
Weakness: CWE-416

Description

libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219.

Affected products

libexpat project libexpat: before 2.8.2 — fixed in 2.8.2

How to fix

Upgrade to a fixed version: libexpat project libexpat 2.8.2. Check the vendor advisory for mitigations.

References

https://github.com/libexpat/libexpat/pull/1278

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