CVE-2025-3891: Mod_auth_openidc: dos via empty post in mod_auth_openidc with oidcpreservepost enabled
First published: Tue Apr 22 2025(Updated: )
A flaw was found in the mod_auth_openidc module for Apache httpd. This flaw allows a remote, unauthenticated attacker to trigger a denial of service by sending an empty POST request when the OIDCPreservePost directive is enabled. The server crashes consistently, affecting availability.
Credit: secalert@redhat.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Apache HTTP Server | ||
| OpenID mod_auth_openidc |
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2025-3891?
CVE-2025-3891 is considered a critical vulnerability that allows remote, unauthenticated attackers to trigger a denial of service.
How do I fix CVE-2025-3891?
To mitigate CVE-2025-3891, disable the OIDCPreservePost directive in the mod_auth_openidc configuration for Apache httpd.
What impact does CVE-2025-3891 have on my system?
CVE-2025-3891 can cause the Apache server to crash, resulting in a loss of availability for services relying on it.
Which versions of Apache httpd are affected by CVE-2025-3891?
CVE-2025-3891 affects all versions of Apache httpd that utilize the mod_auth_openidc module with the OIDCPreservePost directive enabled.
Can CVE-2025-3891 be exploited remotely?
Yes, CVE-2025-3891 can be exploited remotely by an unauthenticated attacker sending an empty POST request.
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