CVE-2025-3891Network attack vector

Service crash via null Content-Type comparison

Published Apr 29, 2025 · Updated Jun 29, 2026

Denial of service in OpenIDC mod_auth_openidc 2.0.0 through 2.4.13.1 allows remote attackers to crash Apache via a headerless POST. The oidc_original_request_method function passes a null Content-Type value to _oidc_strcmp instead of rejecting the headerless request. Exploitation requires OIDCPreservePost to be enabled and interrupts the Apache service without reported data access or modification.

CVSS severity7.5
High
EPSS probability1.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in OpenIDC mod_auth_openidc 2.0.0 through 2.4.13.1 allows remote attackers to crash Apache via a headerless POST. The oidc_original_request_method function passes a null Content-Type value to _oidc_strcmp instead of rejecting the headerless request. Exploitation requires OIDCPreservePost to be enabled and interrupts the Apache service without reported data access or modification.

The record

CVE
CVE-2025-3891
Published
Apr 29, 2025
Updated
Jun 29, 2026
Vendor
389 Directory Server
Product
Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
Classifications
CWE-248, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 29, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

389 Directory Server · Red Hat Enterprise Linux 8.6 Update Services for SAP SolutionsAffected versions are unavailable in this record.
OpenIDC · mod_auth_openidcversion=2.0.0 <2.4.13.1
389 Directory Server · Red Hat Enterprise Linux 8.8 Update Services for SAP SolutionsAffected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 8.6 Telecommunications Update ServiceAffected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 10Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 9.2 Update Services for SAP SolutionsAffected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 9.4 Extended Update SupportAffected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update SupportAffected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 8.2 Advanced Update SupportAffected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 9.0 Update Services for SAP SolutionsAffected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 8.8 Telecommunications Update ServiceAffected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportAffected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.

Published CVSS scores

5.3GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
7.5Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-248Uncaught Exception
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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