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Fencer Intel
high 7.5

CVE-2025-3891 json

Mod_auth_openidc: dos via empty post in mod_auth_openidc with oidcpreservepost enabled

published last yr. modified 5d ago also BIT-apache-2025-3891 , EUVD-2025-13653 , GHSA-x7cf-8wgv-5j86

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

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 server crashes consistently, affecting availability.

Patch / fix

  • OpenIDC mod_auth_openidc 2.4.13.1
  • Red Hat Red Hat Enterprise Linux 8 8100020250426100353.489197e6
  • Red Hat Red Hat Enterprise Linux 8.2 Advanced Update Support 8020020250612174445.4cda2c84
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 8040020250618101351.522a0ee4
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 8060020250617090503.ad008a3a
  • Red Hat Red Hat Enterprise Linux 8.6 Telecommunications Update Service 8060020250617090503.ad008a3a
  • Red Hat Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions 8060020250617090503.ad008a3a
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service 8080020250617090716.63b34585
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 8080020250617090716.63b34585
  • Red Hat Red Hat Enterprise Linux 9 0:2.4.10-1.el9_6.2
  • Red Hat Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions 0:2.4.9.4-1.el9_0.3
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:2.4.9.4-1.el9_2.3
  • Red Hat Red Hat Enterprise Linux 9.4 Extended Update Support 0:2.4.9.4-4.el9_4.2
  • libapache2-mod-auth-openidc Debian 12 2.4.12.3-2+deb12u4
  • libapache2-mod-auth-openidc Debian 14, Debian 13 2.4.14.2-1

debian advisories DEBIAN-CVE-2025-3891

  • mod_auth_openidc RHEL 9 2.4.10-1.el9_6.2
  • cjose RHEL 8 0.6.1-4.module+el8.10.0+21813+b5444eb8
  • mod_auth_openidc RHEL 8 2.4.9.4-8.module+el8.10.0+23056+decb09b1
  • cjose RHEL 8.8 TUS, RHEL 8.8 E4S 0.6.1-3.module+el8.8.0+19464+578f4546
  • mod_auth_openidc RHEL 8.8 TUS, RHEL 8.8 E4S 2.4.9.4-1.module+el8.8.0+23294+baa6f818.2
  • mod_auth_openidc RHEL 9.4 EUS 2.4.9.4-4.el9_4.2
  • mod_auth_openidc RHEL 9.2 E4S 2.4.9.4-1.el9_2.3
  • cjose RHEL 8.2 AUS 0.6.1-3.module+el8.2.0+19461+3a40b6ee

red hat advisories RHSA-2025:10010RHSA-2025:10007RHSA-2025:10008RHSA-2025:10006RHSA-2025:10003RHSA-2025:10004

  • apache2-mod_auth_openidc SLE Module for Server Applications 15 SP7, SLE Module for Server Applications 15 SP6, openSUSE Leap 15.6 2.4.17.1-150600.16.14.1
  • apache2-mod_auth_openidc SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES for SAP 15 SP3 +11 more 2.3.8-150100.3.34.1
  • apache2-mod_auth_openidc SLE Module for Server Applications 15 SP7, SLE Module for Server Applications 15 SP6, openSUSE Leap 15.6 2.3.8-150600.16.11.1
  • apache2-mod_auth_openidc SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 2.4.0-7.22.1

suse advisories SUSE-SU-2025:4532-1SUSE-SU-2025:01962-1SUSE-SU-2025:01953-1SUSE-SU-2025:01585-1

  • mod_auth_openidc AlmaLinux 9 2.4.10-1.el9_6.2
  • cjose AlmaLinux 8 0.6.1-4.module_el8.9.0+3631+0ced13d7
  • cjose AlmaLinux 8 0.6.1-4.module_el8.10.0+3881+234adf82
  • mod_auth_openidc AlmaLinux 8 2.4.9.4-8.module_el8.10.0+3988+526f0275

almalinux advisories ALSA-2025:9396ALSA-2025:4597

  • mod_auth_openidc Rocky Linux 9 2.4.10-1.el9_6.2
  • cjose Rocky Linux 8 0.6.1-4.module+el8.9.0+1384+4b58c166
  • mod_auth_openidc Rocky Linux 8 2.4.9.4-8.module+el8.10.0+1976+99abe5eb

rocky linux advisories RLSA-2025:9396RLSA-2025:4597

Is CVE-2025-3891 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-3891 updated cvss 7.5

mod_auth_openidc: DoS via Empty POST in mod_auth_openidc with OIDCPreservePost Enabled

  • Red Hat Enterprise Linux 10 mod_auth_openidc
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux AppStream (v. 8) cjose 0.6.1-4.module+el8.10.0+21813+b5444eb8, mod_auth_openidc 2.4.9.4-8.module+el8.10.0+23056+decb09b1
    fixed: vendor fix RHSA-2025:4597
  • Red Hat Enterprise Linux AppStream (v. 9) mod_auth_openidc 2.4.10-1.el9_6.2
    fixed: vendor fix RHSA-2025:9396
  • Red Hat Enterprise Linux AppStream AUS (v. 8.2) cjose 0.6.1-3.module+el8.2.0+19461+3a40b6ee, mod_auth_openidc 2.4.9.4-2.module+el8.2.0+23265+3c1fe64f
    fixed: vendor fix RHSA-2025:10006
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) cjose 0.6.1-3.module+el8.4.0+19462+14bde120, mod_auth_openidc 2.4.9.4-1.module+el8.4.0+23303+cbb1cd49.2
    fixed: vendor fix RHSA-2025:10004
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) cjose 0.6.1-3.module+el8.6.0+19463+7d2e1f9c, mod_auth_openidc 2.4.9.4-1.module+el8.6.0+23293+9b46d3da.2 Red Hat Enterprise Linux AppStream E4S (v.8.6) cjose 0.6.1-3.module+el8.6.0+19463+7d2e1f9c, mod_auth_openidc 2.4.9.4-1.module+el8.6.0+23293+9b46d3da.2
    fixed: vendor fix RHSA-2025:10003
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) cjose 0.6.1-3.module+el8.8.0+19464+578f4546, mod_auth_openidc 2.4.9.4-1.module+el8.8.0+23294+baa6f818.2
    fixed: vendor fix RHSA-2025:10010
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) mod_auth_openidc 2.4.9.4-1.el9_0.3
    fixed: vendor fix RHSA-2025:10002
show 5 more
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) mod_auth_openidc 2.4.9.4-1.el9_2.3
    fixed: vendor fix RHSA-2025:10008
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) mod_auth_openidc 2.4.9.4-4.el9_4.2
    fixed: vendor fix RHSA-2025:10007
  • Red Hat Enterprise Linux AppStream TUS (v.8.6) cjose 0.6.1-3.module+el8.6.0+19463+7d2e1f9c, mod_auth_openidc 2.4.9.4-1.module+el8.6.0+23293+9b46d3da.2
    fixed: vendor fix RHSA-2025:10003
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) cjose 0.6.1-3.module+el8.8.0+19464+578f4546, mod_auth_openidc 2.4.9.4-1.module+el8.8.0+23294+baa6f818.2
    fixed: vendor fix RHSA-2025:10010
  • Red Hat Enterprise Linux 7 mod_auth_openidc
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
last yr.

Exploit prediction

1.60% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami apache — no fix listed

Affected products

  • OpenIDC mod_auth_openidc
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 8.2 Advanced Update Support
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.6 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.4 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 7

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.