Use After Free Affecting thunderbird package, versions <0:140.12.0-1.amzn2.0.1


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.18% (9th percentile)

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  • Snyk IDSNYK-AMZN2-THUNDERBIRD-17883957
  • published8 Jul 2026
  • disclosed19 Jun 2026

Introduced: 19 Jun 2026

CVE-2026-56131  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2 thunderbird to version 0:140.12.0-1.amzn2.0.1 or higher.
This issue was patched in ALAS2-2026-3795.

NVD Description

Note: Versions mentioned in the description apply only to the upstream thunderbird package and not the thunderbird package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2 relevant fixed versions and status.

libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_ResumeParser from within handlers in cases of a policy violation. Thus, a use-after-free can occur (similar to the CVE-2026-50219 situation).

CVSS Base Scores

version 3.1