CVE-2026-56412: 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.

Overview

Severity

Medium (CVSS 4.9)

CVSS Vector

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

Exploit Status

Not Exploited

Patch Tuesday

2026-Jun

Released

2026-06-27

Last Updated

2026-06-28

EPSS Score

0.10% (percentile: 1.3%)

Affected Products (5)

Other

• 21491-17084
• 21492-17084

Open Source Software

• azl3 expat 2.6.4-6 on Azure Linux 3.0
• azl3 cmake 3.30.3-13 on Azure Linux 3.0
• azl3 python3 3.12.9-11 on Azure Linux 3.0

Revision History

• 2026-06-27: Information published.
• 2026-06-28: Information published.