Vulnerability in Apache HTTP Server
CVE-2025-3891
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.016 (74.5th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 74th percentile — 74.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.014 · newest: 0.016 · change: +0.002
Affected products
- Apache HTTP Server
- Debian Linux — versions 11.0
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8 — versions 8100020250426100353.489197e6
- Red Hat Enterprise Linux 8.2 Advanced Update Support — versions 8020020250612174445.4cda2c84
- Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support — versions 8040020250618101351.522a0ee4
- Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support — versions 8060020250617090503.ad008a3a
- Red Hat Enterprise Linux 8.6 Telecommunications Update Service — versions 8060020250617090503.ad008a3a
- Red Hat Enterprise Linux 8.6 Update Services For SAP Solutions — versions 8060020250617090503.ad008a3a
Weakness classification (CWE)
Public proof-of-concept exploits
References
- access.redhat.com/errata/RHSA-2025:10002 (vendor-advisory)
- access.redhat.com/errata/RHSA-2025:10003 (vendor-advisory)
- access.redhat.com/errata/RHSA-2025:10004 (vendor-advisory)
- access.redhat.com/errata/RHSA-2025:10006 (vendor-advisory)
- access.redhat.com/errata/RHSA-2025:10007 (vendor-advisory)
- access.redhat.com/errata/RHSA-2025:10008 (vendor-advisory)
- access.redhat.com/errata/RHSA-2025:10010 (vendor-advisory)
- access.redhat.com/errata/RHSA-2025:4597 (vendor-advisory, Third Party Advisory)
- access.redhat.com/errata/RHSA-2025:9396 (vendor-advisory)
- access.redhat.com/security/cve/CVE-2025-3891 (Third Party Advisory, vdb-entry)
Frequently asked questions
- What is CVE-2025-3891?
- CVE-2025-3891 is a high-severity vulnerability in Apache HTTP Server, classified under CWE-248. CVSS score: 7.5/10. Published 2025-04-29.
- How severe is CVE-2025-3891?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2025-3891 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.