CVE-2026-62911: microsoft exchange_server Authentication Bypass by Capture-replay

Vulnerability summary

CVE-2026-62911 is a high (CVSS 8.0) Authentication Bypass by Capture-replay vulnerability in microsoft exchange_server. EPSS estimates a 0.69% chance of exploitation in the next 30 days, higher than 52.3% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 11-08-2026
   PublishedVulnerability first disclosed.
2. 08-10-2026
   Last modifiedVulnerability information updated.

Description

Authentication bypass by capture-replay in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.

• CWE-294Authentication Bypass by Capture-replayA capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).