Microsoft has pulled the November 2024 Exchange security updates due to email delivery issues on servers using custom mail flow rules. The issue affects customers using transport rules or data loss protection (DLP) rules, which will stop periodically after installing the updates. Microsoft has paused the rollout of the updates and is working on a permanent fix.
In addition, Microsoft has disclosed a high-severity Exchange Server vulnerability (CVE-2024-49040) that can allow attackers to forge legitimate senders on incoming emails. While the vulnerability has not been patched, Microsoft says servers will now detect and prepend a warning to malicious emails after installing the Exchange Server November 2024 Security Update (SU).
Microsoft also fixed four zero-days during the November 2024 Patch Tuesday, two of which were actively exploited in attacks and three were publicly disclosed. The update also addressed four critical vulnerabilities, including two remote code execution flaws and two elevations of privileges bugs.
