Apache mod_auth_openidc POST Crash via OIDCPreservePost
CVE-2025-3891 Published on April 29, 2025

Mod_auth_openidc: dos via empty post in mod_auth_openidc with oidcpreservepost enabled
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.

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Vulnerability Analysis

CVE-2025-3891 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Timeline

Reported to Red Hat.

Made public. 7 days later.

Weakness Type

Uncaught Exception

An exception is thrown from a function, but it is not caught. When an exception is not caught, it may cause the program to crash or expose sensitive information.


Products Associated with CVE-2025-3891

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Exploit Probability

EPSS
0.52%
Percentile
66.37%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.