Apache HTTP Server: OOB Read in `merge_response_headers` can cause crash
CVE-2026-43951

6.5MEDIUM

Key Information:

Vendor

Apache
Status
Apache Http Server
Vendor
CVE Published:
8 June 2026

What is CVE-2026-43951?

Out-of-bounds Read vulnerability in Apache HTTP Server with mod_headers and mod_mime and multiple response languages.

This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67.

Affected Version(s)

Apache HTTP Server 2.4.0 <= 2.4.67

References

https://httpd.apache.org/security/vulnerabilities_24.html
vendor-advisory

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Zhenpeng (Leo) Lin at depthfirst
.