---
id: CVE-2025-3891
title: A flaw was found in the mod_auth_openidc module for Apache httpd
summary: >-
  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 ser…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-248
vendor: apache
product: http_server
affected:
  - http_server
  - enterprise_linux = 7.0
  - enterprise_linux = 8.0
  - enterprise_linux = 9.0
  - debian_linux = 11.0
published: '2025-04-29'
updated: '2026-06-25'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-3891'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2025:10002'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2025:10003'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2025:10004'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2025:10006'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2025:10007'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2025:10008'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2025:10010'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2025:4597'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2025:9396'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2025-3891'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2361633'
    label: secalert@redhat.com
  - url: >-
      https://github.com/OpenIDC/mod_auth_openidc/commit/6a0b5f66c87184dfe0e4400f6bdd46a82dc0ec2b
    label: secalert@redhat.com
  - url: >-
      https://github.com/OpenIDC/mod_auth_openidc/security/advisories/GHSA-x7cf-8wgv-5j86
    label: secalert@redhat.com
  - url: 'https://lists.debian.org/debian-lts-announce/2025/05/msg00007.html'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01424
epssPercentile: 0.71759
ingestedAt: '2026-06-29T13:24:34.201Z'
---

## Overview

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.

## Affected

- `http_server`
- `enterprise_linux = 7.0`
- `enterprise_linux = 8.0`
- `enterprise_linux = 9.0`
- `debian_linux = 11.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.