What is CVE-2026-28780?

CVE-2026-28780 is a critical-severity vulnerability in Apache Http_server, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-05-05.

How severe is CVE-2026-28780?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Apache Http_server

CVE-2026-28780

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 co…

Vulnerability class: Buffer Overflow

EPSS: 0.000 (6.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Apache Http_server
Apache Software Foundation Http Server — versions 0

Weakness classification (CWE)

CWE-122 — Heap-based Buffer Overflow

References

security@apache.org (vendor-advisory, Release Notes, Vendor Advisory)
af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2026-28780?: CVE-2026-28780 is a critical-severity vulnerability in Apache Http_server, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-05-05.
How severe is CVE-2026-28780?: Critical severity. CVSS v3 base score is 9.8 out of 10.