CVE-2026-44631: Apache HTTP Server: Heap Underflow in `ap_regname` via Signed Char Overflow

Severity: critical (CVSS 9.8 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-124

Description

Buffer Underwrite vulnerability in Apache HTTP Server on crafted regular expressions in the configuration. This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67. Users are recommended to upgrade to version 2.4.68, which fixes the issue.

Affected products

Apache HTTP Server: from 2.4.0 before 2.4.68 — fixed in 2.4.68

How to fix

Upgrade to a fixed version: Apache HTTP Server 2.4.68. Check the vendor advisory for mitigations.

References

https://httpd.apache.org/security/vulnerabilities_24.html
http://www.openwall.com/lists/oss-security/2026/06/08/14

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