# CVE-2025-3891: Mod_auth_openidc: dos via empty post in mod_auth_openidc with oidcpreservepost enabled > Remote attackers can crash the Apache server by sending empty POST requests when the OIDCPreservePost directive is enabled. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 29 Apr 2025 - **Updated:** 29 Jun 2026 - **Also known as:** ALSA-2025:4597, ALSA-2025:9396, BIT-apache-2025-3891, CLSA-2025-1752247075, DEBIAN-CVE-2025-3891, DLA-4155-1, DSA-5917-1, GHSA-v96g-5j57-774c, GHSA-x7cf-8wgv-5j86, MINI-63j4-rp82-fv46, RHSA-2025:10002, RHSA-2025:10003, RHSA-2025:10004, RHSA-2025:10006, RHSA-2025:10007, RHSA-2025:10008, RHSA-2025:10010, RHSA-2025:4597, RHSA-2025:9396, RLSA-2025:4597, RLSA-2025:9396, SUSE-SU-2025:01585-1, SUSE-SU-2025:01953-1, SUSE-SU-2025:01962-1, UBUNTU-CVE-2025-3891 ## 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 (Uncaught Exception) ## Which versions are affected by CVE-2025-3891? 1 open source package ship an affected version, including apache. It affects 3 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `apache` | Bitnami | All versions | None | | `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: Apache Http Server, Debian Debian Linux, Redhat Enterprise Linux. ## How do I fix CVE-2025-3891? Apply the vendor's patch. ## 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 - [CVE-2021-42013](https://insights.sbomify.com/CVE-2021-42013/): Apache HTTP Server Path Traversal (critical 9.8, exploited in the wild) - [CVE-2024-38475](https://insights.sbomify.com/CVE-2024-38475/): Apache HTTP Server Improper Escaping of Output (critical 9.1, exploited in the wild) - [CVE-2021-40438](https://insights.sbomify.com/CVE-2021-40438/): Apache HTTP Server-Side Request Forgery (SSRF) (critical 9.0, exploited in the wild) - [CVE-2019-0211](https://insights.sbomify.com/CVE-2019-0211/): Apache HTTP Server Privilege Escalation (high 7.8, exploited in the wild) - [CVE-2021-41773](https://insights.sbomify.com/CVE-2021-41773/): Apache HTTP Server Path Traversal (high 7.5, exploited in the wild) ## Fix prompt for AI coding agents ```text 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) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2025-3891 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-3891 - OSV: https://osv.dev/vulnerability/CVE-2025-3891 --- From sbomify Insights: https://insights.sbomify.com/CVE-2025-3891/ Summaries are generated and may contain mistakes; the official description above is the record.