CVE-2026-28780 Apache CVE debrief

Who should care

Apache HTTP Server users, administrators of web servers, and security teams should be aware of this critical vulnerability. The vulnerability's high CVSS score and potential for remote exploitation make it a priority for patching. Affected users should assess their exposure and apply the fix promptly.

Technical summary

The vulnerability is a heap-based buffer overflow in mod_proxy_ajp of Apache HTTP Server. When mod_proxy_ajp connects to a malicious AJP server, that server can send a crafted AJP message back to mod_proxy_ajp, causing it to write 4 attacker-controlled bytes after the end of a heap-based buffer. This issue is particularly severe due to its potential for remote exploitation and high CVSS score of 9.8. The CWE-122 and CWE-787 weaknesses are associated with this vulnerability.

Defensive priority

This vulnerability should be prioritized for immediate patching due to its critical severity and potential for remote exploitation. Affected Apache HTTP Server users should upgrade to version 2.4.67 as soon as possible to mitigate the risk.

Recommended defensive actions

• Upgrade Apache HTTP Server to version 2.4.67 or later
• Assess exposure and prioritize patching for affected versions
• Monitor for potential exploitation attempts
• Review and update incident response plans
• Apply compensating controls if immediate patching is not feasible

Evidence notes

The CVE-2026-28780 vulnerability is well-documented in the NVD and CVE records. Multiple sources, including Apache and Red Hat, provide information on the vulnerability and its fix. The evidence suggests a high level of confidence in the vulnerability's existence and impact.

Official resources