Disclosure summary
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.
Source-reported weakness categories
CWE-416
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
Microsoft Security Updates (CVRF) · 2026-Aug
Open original source · Updated Aug 23, 2026
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.
Maximum of vendor-reported product scores; products and fixed builds are associations, not a universal affected-version statement.
Microsoft maximum product score: 4.9
| Vendor | Product / association | Version / bounds |
|---|---|---|
| Microsoft update guide | azl3 expat 2.8.2-1 on Azure Linux 3.0 | (MSRC status code 3) |
| Microsoft update guide | azl3 cmake 3.30.3-15 on Azure Linux 3.0 | (MSRC status code 3) |
| Microsoft update guide | azl3 python3 3.12.9-14 on Azure Linux 3.0 | (MSRC status code 3) |
Original records & references
- NIST NVD record
- CVE Program record
- msrc.microsoft.com — Vendor advisory
PUBLISHED 2026-08-21T10:02:28-04:00
MODIFIED 2026-08-23T21:44:07-04:00
INGESTED 2026-10-08T12:40:11-04:00