Critical severity · published Jun 8, 2026
CVE-2026-44631
Apache HTTP Server: Heap Underflow in `ap_regname` via Signed Char Overflow
9.8
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
HS
HTTP Server · Apache
2.4.0 through 2.4.67 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-44631
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-44631
Vendor Advisory
https://httpd.apache.org/security/vulnerabilities_24.html
Mailing List
http://www.openwall.com/lists/oss-security/2026/06/08/14
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