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.
CVSS Details
- CVSS 3.1 Base Score: 5.9
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade expat | Jun 29, 2026 | Jun 21, 2026 |
| Amazon Linux Ami 2 | — | Upgrade firefoxUpgrade thunderbird | Jul 8, 2026 | Jul 8, 2026 |
| Amazon_linux_2023 | — | Upgrade expat-develUpgrade expat-debuginfoUpgrade firefox-debuginfoUpgrade expat-debugsourceUpgrade firefox-debugsourceUpgrade firefoxUpgrade expat-staticUpgrade expat | Jul 8, 2026 | Jun 21, 2026 |
| Debian | — | Upgrade expat | Aug 2, 2026 | Aug 2, 2026 |
| Freebsd | — | Upgrade linux-c7-expatUpgrade expatUpgrade linux-rl9-expat | Jun 30, 2026 | Jun 28, 2026 |
| Ibm Aix | — | Apply the fix or workaround for python_advisory20 | Jul 15, 2026 | Jul 14, 2026 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Jun 21, 2026 |
| Ubuntu | — | Upgrade lib64expat1 (Ubuntu Pro)Upgrade libexpat1-dev (Ubuntu Pro)Upgrade libexpat1 (Ubuntu Pro)Upgrade libexpat1Upgrade expatUpgrade expat (Ubuntu Pro)Upgrade lib64expat1-dev (Ubuntu Pro)Upgrade libexpat1-dev | Sep 22, 2026 | Sep 21, 2026 |
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