Authentication Bypass by Capture-replay in Apache HTTP Server - CVE-2026-73636
Published: October 1, 2026
Vulnerability identifier: #VU153107
CSH Severity: Medium
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-73636
CWE-ID: CWE-294
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass authentication.
The vulnerability exists due to improper handling of one-time nonces in mod_auth_digest when AuthDigestNonceLifetime is set to 0. A remote attacker can replay captured digest authentication credentials in crafted requests that trigger garbage collection of the client's shared-memory entry to bypass authentication.
Exploitation requires a man-in-the-middle position.
Affected software
Apache HTTP Server
How to mitigate CVE-2026-73636
Install security update from vendor's website.
Apache HTTP Server - update to 2.4.69