CVE-2026-28780: Apache HTTP Server

Critical severity, CVSS 9.8. EPSS: 1.6% chance of exploitation in the next 30 days.

Heap-based Buffer Overflow vulnerability in mod_proxy_ajp of Apache HTTP Server. If mod_proxy_ajp connects to a malicious AJP server this AJP server can send a malicious AJP message back to mod_proxy_ajp and cause it to write 4 attacker controlled bytes after the end of a heap based buffer. This issue affects Apache HTTP Server: through 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the issue.

Affected products

• Apache HTTP Server: before 2.4.67 (fixed in 2.4.67)

Published 2026-05-05. Last modified 2026-09-14.