Session Fixation in mod_auth_openidc - #VU142421
Published: August 13, 2026
Vulnerability identifier: #VU142421
CSH Severity: Medium
CVSS v4: 7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-384
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to hijack a victim\'s authenticated session.
The vulnerability exists due to improper session management in login session handling when processing authentication for a browser presenting an attacker-fixed session identifier. A remote attacker can set a chosen session cookie and wait for the victim to authenticate to hijack a victim\'s authenticated session.
The attacker must be able to set a cookie for the host before the victim logs in.
Affected software
mod_auth_openidc
Remediation
Install security update from vendor's website.
mod_auth_openidc - update to 2.4.20.1