In nspawn in systemd 233 through 259 before 260, an escape-to-host action can occur via a crafted optional config file.

• azl3 systemd 255-26 on Azure Linux 3.0

• cbl2 systemd 250.3-24 on CBL Mariner 2.0

• azl3 systemd 255-27 on Azure Linux 3.0

• azl3 systemd 255-30 on Azure Linux 3.0

• cbl2 systemd 250.3-24 on CBL-Mariner 2.0

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 8, 2026 at 9:05 AM UTC
   • The vendor changed the advisory title.
   • Added affected products: azl3 systemd 255-30 on Azure Linux 3.0, cbl2 systemd 250.3-24 on CBL-Mariner 2.0.
   • Added fixed versions: 255-28, 255-30.
   • The vendor changed its remediation guidance.

1. Apr 12, 2026 at 1:01 AM UTC
   Published by Microsoft Security Response Center

   The publication date reported by the vendor.

2. Sep 25, 2026 at 2:45 AM UTC
   Updated by Microsoft Security Response Center

   The vendor changed the advisory after it was first published.

3. Sep 27, 2026 at 11:11 PM UTC
   Added to SecurityAlert

   We collected the advisory from the official source.

4. Nov 10, 2026 at 2:00 AM UTC
   Confirmed at the source

   Our collector saw this advisory during a later source check.