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.

• 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

SecurityAlert records field-level changes from the point we begin following a bulletin. Earlier vendor changes may not have a field-by-field record.

1. Oct 22, 2026 at 7:40 AM UTC
   • The vendor changed the advisory's last-updated date.

1. Jun 27, 2026 at 1:07 AM UTC
   Published by Microsoft Security Response Center

   The publication date reported by the vendor.

2. Sep 28, 2026 at 11:20 AM UTC
   Added to SecurityAlert

   We collected the advisory from the official source.

3. Oct 22, 2026 at 1:09 AM UTC
   Updated by Microsoft Security Response Center

   The vendor changed the advisory after it was first published.

4. Nov 11, 2026 at 2:20 AM UTC
   Confirmed at the source

   Our collector saw this advisory during a later source check.