CVE-2026-34355: Apache HTTP Server: mod_proxy_html buffer overflow

[Eric Covener <covener () apache org>]

Severity: moderate 

Affected versions:

- Apache HTTP Server 2.4.0 through 2.4.67

Description:

A buffer overflow in mod_proxy_html in Apache HTTP Server 2.4.67 and earlier allows an attack by an untrusted backend.
Users are recommended to upgrade to version 2.4.68, which fixes this issue.

Credit:

Elhanan Haenel (finder)
Junhui Lee (finder)

References:

https://httpd.apache.org/security/vulnerabilities_24.html
https://httpd.apache.org/
https://www.cve.org/CVERecord?id=CVE-2026-34355

Timeline:

2026-03-21: Report received
2026-06-04: fixed in 2.4.x by r1934977
2026-06-08: 2.4.68 released