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

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-08 · updated 2026-07-23
Weakness: CWE-125

Description

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 products

Apache HTTP Server: from 2.4.0 through 2.4.67

References

https://httpd.apache.org/security/vulnerabilities_24.html
http://www.openwall.com/lists/oss-security/2026/06/08/10

Get alerted when CVE-2026-43951 or the next vulnerability affects your stack