CVE-2025-3891 Mod_auth_openidc: dos via empty post in mod_auth_openidc with oidcpreservepost enabled
High 7.5
Published
Updated
Check this codebase for CVE-2025-3891 and fix it if it is affected.
What it is: CVE-2025-3891 is a high-severity denial of service vulnerability in Apache Http Server, published on 29 Apr 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-3891 in the wild and no public exploit code.
Affected packages and fixed versions:
- apache (Bitnami): affected all versions; no fix listed
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2025-3891/ (Markdown: https://insights.sbomify.com/CVE-2025-3891/index.md)
Remote attackers can crash the Apache server by sending empty POST requests when the OIDCPreservePost directive is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-3891?
CVE-2025-3891 is a high-severity denial of service vulnerability in Apache Http Server, published on 29 Apr 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-248
Which versions are affected by CVE-2025-3891?
1 open source package ship an affected version, including apache. It affects 3 products.
| Package | Affected | Fixed in |
|---|---|---|
apache Bitnami | All versions | None |
Linux distribution packages (39)
cjose AlmaLinux:8 | All versions | 0.6.1-4.module_el8.10.0+3881+234adf82 |
cjose AlmaLinux:8 | All versions | 0.6.1-4.module_el8.9.0+3631+0ced13d7 |
cjose-devel AlmaLinux:8 | All versions | 0.6.1-4.module_el8.10.0+3881+234adf82 |
cjose-devel AlmaLinux:8 | All versions | 0.6.1-4.module_el8.9.0+3631+0ced13d7 |
mod_auth_openidc AlmaLinux:8 | All versions | 2.4.9.4-8.module_el8.10.0+3988+526f0275 |
mod_auth_openidc AlmaLinux:9 | All versions | 2.4.10-1.el9_6.2 |
cjose Red Hat:enterprise_linux:8::appstream | All versions | 0:0.6.1-4.module+el8.10.0+21813+b5444eb8 |
cjose-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:0.6.1-4.module+el8.10.0+21813+b5444eb8 |
cjose-debugsource Red Hat:enterprise_linux:8::appstream | All versions | 0:0.6.1-4.module+el8.10.0+21813+b5444eb8 |
cjose-devel Red Hat:enterprise_linux:8::appstream | All versions | 0:0.6.1-4.module+el8.10.0+21813+b5444eb8 |
mod_auth_openidc Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.9.4-8.module+el8.10.0+23056+decb09b1 |
mod_auth_openidc-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.9.4-8.module+el8.10.0+23056+decb09b1 |
mod_auth_openidc-debugsource Red Hat:enterprise_linux:8::appstream | All versions | 0:2.4.9.4-8.module+el8.10.0+23056+decb09b1 |
mod_auth_openidc Red Hat:enterprise_linux:9::appstream | All versions | 0:2.4.10-1.el9_6.2 |
mod_auth_openidc-debuginfo Red Hat:enterprise_linux:9::appstream | All versions | 0:2.4.10-1.el9_6.2 |
mod_auth_openidc-debugsource Red Hat:enterprise_linux:9::appstream | All versions | 0:2.4.10-1.el9_6.2 |
cjose Red Hat:rhel_aus:8.2::appstream | All versions | 0:0.6.1-3.module+el8.2.0+19461+3a40b6ee |
cjose-debuginfo Red Hat:rhel_aus:8.2::appstream | All versions | 0:0.6.1-3.module+el8.2.0+19461+3a40b6ee |
cjose-debugsource Red Hat:rhel_aus:8.2::appstream | All versions | 0:0.6.1-3.module+el8.2.0+19461+3a40b6ee |
cjose-devel Red Hat:rhel_aus:8.2::appstream | All versions | 0:0.6.1-3.module+el8.2.0+19461+3a40b6ee |
mod_auth_openidc Red Hat:rhel_aus:8.2::appstream | All versions | 0:2.4.9.4-2.module+el8.2.0+23265+3c1fe64f |
mod_auth_openidc-debuginfo Red Hat:rhel_aus:8.2::appstream | All versions | 0:2.4.9.4-2.module+el8.2.0+23265+3c1fe64f |
mod_auth_openidc-debugsource Red Hat:rhel_aus:8.2::appstream | All versions | 0:2.4.9.4-2.module+el8.2.0+23265+3c1fe64f |
cjose Red Hat:rhel_aus:8.4::appstream | All versions | 0:0.6.1-3.module+el8.4.0+19462+14bde120 |
cjose-debuginfo Red Hat:rhel_aus:8.4::appstream | All versions | 0:0.6.1-3.module+el8.4.0+19462+14bde120 |
cjose-debugsource Red Hat:rhel_aus:8.4::appstream | All versions | 0:0.6.1-3.module+el8.4.0+19462+14bde120 |
cjose-devel Red Hat:rhel_aus:8.4::appstream | All versions | 0:0.6.1-3.module+el8.4.0+19462+14bde120 |
mod_auth_openidc Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.4.9.4-1.module+el8.4.0+23303+cbb1cd49.2 |
mod_auth_openidc-debuginfo Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.4.9.4-1.module+el8.4.0+23303+cbb1cd49.2 |
mod_auth_openidc-debugsource Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.4.9.4-1.module+el8.4.0+23303+cbb1cd49.2 |
cjose Red Hat:rhel_aus:8.6::appstream | All versions | 0:0.6.1-3.module+el8.6.0+19463+7d2e1f9c |
cjose-debuginfo Red Hat:rhel_aus:8.6::appstream | All versions | 0:0.6.1-3.module+el8.6.0+19463+7d2e1f9c |
cjose-debugsource Red Hat:rhel_aus:8.6::appstream | All versions | 0:0.6.1-3.module+el8.6.0+19463+7d2e1f9c |
cjose-devel Red Hat:rhel_aus:8.6::appstream | All versions | 0:0.6.1-3.module+el8.6.0+19463+7d2e1f9c |
mod_auth_openidc Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.4.9.4-1.module+el8.6.0+23293+9b46d3da.2 |
mod_auth_openidc-debuginfo Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.4.9.4-1.module+el8.6.0+23293+9b46d3da.2 |
mod_auth_openidc-debugsource Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.4.9.4-1.module+el8.6.0+23293+9b46d3da.2 |
cjose Red Hat:rhel_e4s:8.6::appstream | All versions | 0:0.6.1-3.module+el8.6.0+19463+7d2e1f9c |
cjose-debuginfo Red Hat:rhel_e4s:8.6::appstream | All versions | 0:0.6.1-3.module+el8.6.0+19463+7d2e1f9c |
Products include Apache Http Server, Debian Debian Linux, Redhat Enterprise Linux.
How do I fix CVE-2025-3891?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-3891 being exploited?
There is no known exploitation of CVE-2025-3891 in the wild and no public exploit code.
Other vulnerabilities in Apache Http Server
Sources
Also known as ALSA-2025:4597, ALSA-2025:9396, BIT-apache-2025-3891, CLSA-2025-1752247075, DEBIAN-CVE-2025-3891, DLA-4155-1 and 19 more.