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.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade expat | Sep 1, 2026 | Aug 20, 2026 |
| Amazon_linux_2023 | — | Upgrade expat-staticUpgrade expat-develUpgrade expat-debuginfoUpgrade firefoxUpgrade expat-debugsourceUpgrade expatUpgrade firefox-debugsourceUpgrade firefox-debuginfo | Sep 1, 2026 | Aug 20, 2026 |
| Debian | — | Upgrade expat | Sep 1, 2026 | Sep 1, 2026 |
| Ibm Aix | — | Apply the fix or workaround for python_advisory21 | Sep 15, 2026 | Sep 15, 2026 |
| Redhat_linux | — | No solution exists | Aug 28, 2026 | Aug 20, 2026 |
| Ubuntu | — | Upgrade expat (Ubuntu Pro)Upgrade libexpat1-dev (Ubuntu Pro)Upgrade libexpat1 (Ubuntu Pro)Upgrade libexpat1-devUpgrade libexpat1Upgrade lib64expat1-dev (Ubuntu Pro)Upgrade lib64expat1 (Ubuntu Pro)Upgrade expat | Sep 24, 2026 | Aug 20, 2026 |
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