Use-after-free in Apache HTTP Server - CVE-2026-73637
Published: October 1, 2026
Vulnerability identifier: #VU153111
CSH Severity: Low
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-73637
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to use-after-free in mod_auth_digest when processing concurrent Digest authentication requests. A remote attacker can send concurrent Digest authentication requests to cause a denial of service.
The issue occurs when AuthDigestNcCheck is enabled or AuthDigestNonceLifetime is set to 0.
Affected software
Apache HTTP Server
How to mitigate CVE-2026-73637
Install security update from vendor's website.
Apache HTTP Server - update to 2.4.69