Out-of-bounds read in Apache HTTP Server - CVE-2026-43951
Published: June 8, 2026
Vulnerability identifier: #VU133902
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-43951
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Apache Foundation
Affected software:
Apache HTTP Server
Apache HTTP Server
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to out-of-bounds read in merge_response_headers when processing responses with mod_headers, mod_mime, and multiple response languages. A remote attacker can trigger processing of affected responses to cause a denial of service.
The issue occurs when mod_headers and mod_mime are used with multiple response languages.
How to mitigate CVE-2026-43951
Install security update from vendor's website.