CVE-2026-28780

EUVD-2026-27506
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
9.8 CRITICAL
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 20%
Affected Products (NVD)
VendorProductVersion
apachehttp_server
𝑥
< 2.4.67
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
apache2
bookworm
vulnerable
bookworm (security)
2.4.67-1~deb12u2
fixed
bullseye
vulnerable
bullseye (security)
vulnerable
forky
vulnerable
sid
2.4.67-1
fixed
trixie
vulnerable
trixie (security)
2.4.67-1~deb13u2
fixed
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
apache2
bionic
needs-triage
focal
needs-triage
jammy
Fixed 2.4.52-1ubuntu4.20
released
noble
Fixed 2.4.58-1ubuntu8.12
released
questing
Fixed 2.4.64-1ubuntu3.4
released
resolute
Fixed 2.4.66-2ubuntu2.1
released
trusty
needs-triage
xenial
needs-triage
Common Weakness Enumeration
Vulnerability Media Exposure
References
https://httpd.apache.org/security/vulnerabilities_24.html
http://www.openwall.com/lists/oss-security/2026/05/05/9