# CVE-2026-54789: mod_auth_openidc has out-of-bounds read and write in state cookie parsing > An out-of-bounds read and write in the state cookie parser of mod_auth_openidc allows attackers to potentially execute code or cause denial of service. - **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:** 21 Aug 2026 - **Updated:** 2 Sep 2026 - **Also known as:** ALSA-2026:75581, ALSA-2026:79177, AZL-96984, CLSA-2026-1791839568, CLSA-2026-1792634626, DEBIAN-CVE-2026-54789, GHSA-vgr5-qcpp-x2pr, MGASA-2026-0381, OESA-2026-3009, OESA-2026-3010, OESA-2026-3011, OESA-2026-3012, RHSA-2026:69712, RHSA-2026:69713, RHSA-2026:69715, RHSA-2026:69716, RHSA-2026:69717, RHSA-2026:69718, RHSA-2026:69719, RHSA-2026:69720, RHSA-2026:75581, RHSA-2026:79177, RLSA-2026:75581, RLSA-2026:79177, SUSE-SU-2026:23593-1, SUSE-SU-2026:3915-1, SUSE-SU-2026:3952-1, SUSE-SU-2026:3953-1, UBUNTU-CVE-2026-54789, openSUSE-SU-2026:11582-1, openSUSE-SU-2026:21717-1 ## What is CVE-2026-54789? CVE-2026-54789 is a high-severity memory corruption vulnerability in mod_auth_openidc, published on 21 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description mod_auth_openidc is an OpenID Certified authentication and authorization module for the Apache 2.x HTTP server that implements the OpenID Connect Relying Party functionality. Prior to 2.4.19.4, an out-of-bounds read and a one-byte out-of-bounds write exist in the state-cookie parser of `mod_auth_openidc`. The issue is fixed in version 2.4.19.4 by stopping the scan at the string terminator so a value-less token is rejected. No in-product workarounds are available. As a stop-gap, an upstream reverse proxy or WAF that rejects or normalizes malformed `Cookie` headers (tokens lacking `=`) can reduce exposure, but upgrading is the recommended remediation. Weakness: CWE-787 (Out-of-bounds Write), CWE-125 (Out-of-bounds Read) ## Which versions are affected by CVE-2026-54789? | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `mod_auth_openidc` | AlmaLinux:10 | All versions | 2.4.16.11-1.el10_2.1 | | `mod_auth_openidc` | AlmaLinux:9 | All versions | 2.4.16.11-1.el9_8.1 | | `mod_auth_openidc` | Red Hat:enterprise_linux:10.2 | All versions | 0:2.4.16.11-1.el10_2.1 | | `mod_auth_openidc-debuginfo` | Red Hat:enterprise_linux:10.2 | All versions | 0:2.4.16.11-1.el10_2.1 | | `mod_auth_openidc-debugsource` | Red Hat:enterprise_linux:10.2 | All versions | 0:2.4.16.11-1.el10_2.1 | | `mod_auth_openidc` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.4.16.11-1.el9_8.1 | | `mod_auth_openidc-debuginfo` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.4.16.11-1.el9_8.1 | | `mod_auth_openidc-debugsource` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.4.16.11-1.el9_8.1 | | `mod_auth_openidc` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:2.4.15-4.el10_0.2 | | `mod_auth_openidc-debuginfo` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:2.4.15-4.el10_0.2 | | `mod_auth_openidc-debugsource` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:2.4.15-4.el10_0.2 | | `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+24868+593d10ef.3 | | `mod_auth_openidc-debuginfo` | Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.4.9.4-1.module+el8.4.0+24868+593d10ef.3 | | `mod_auth_openidc-debugsource` | Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.4.9.4-1.module+el8.4.0+24868+593d10ef.3 | | `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+24867+df0294a5.3 | | `mod_auth_openidc-debuginfo` | Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.4.9.4-1.module+el8.6.0+24867+df0294a5.3 | | `mod_auth_openidc-debugsource` | Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.4.9.4-1.module+el8.6.0+24867+df0294a5.3 | | `cjose` | Red Hat:rhel_e4s:8.8::appstream | All versions | 0:0.6.1-3.module+el8.8.0+19464+578f4546 | | `cjose-debuginfo` | Red Hat:rhel_e4s:8.8::appstream | All versions | 0:0.6.1-3.module+el8.8.0+19464+578f4546 | | `cjose-debugsource` | Red Hat:rhel_e4s:8.8::appstream | All versions | 0:0.6.1-3.module+el8.8.0+19464+578f4546 | | `cjose-devel` | Red Hat:rhel_e4s:8.8::appstream | All versions | 0:0.6.1-3.module+el8.8.0+19464+578f4546 | | `mod_auth_openidc` | Red Hat:rhel_e4s:8.8::appstream | All versions | 0:2.4.9.4-1.module+el8.8.0+24885+7d8e9f68.3 | | `mod_auth_openidc-debuginfo` | Red Hat:rhel_e4s:8.8::appstream | All versions | 0:2.4.9.4-1.module+el8.8.0+24885+7d8e9f68.3 | | `mod_auth_openidc-debugsource` | Red Hat:rhel_e4s:8.8::appstream | All versions | 0:2.4.9.4-1.module+el8.8.0+24885+7d8e9f68.3 | | `mod_auth_openidc` | Red Hat:rhel_e4s:9.2::appstream | All versions | 0:2.4.9.4-1.el9_2.4 | | `mod_auth_openidc-debuginfo` | Red Hat:rhel_e4s:9.2::appstream | All versions | 0:2.4.9.4-1.el9_2.4 | | `mod_auth_openidc-debugsource` | Red Hat:rhel_e4s:9.2::appstream | All versions | 0:2.4.9.4-1.el9_2.4 | | `mod_auth_openidc` | Red Hat:rhel_e4s:9.4::appstream | All versions | 0:2.4.9.4-4.el9_4.3 | | `mod_auth_openidc-debuginfo` | Red Hat:rhel_e4s:9.4::appstream | All versions | 0:2.4.9.4-4.el9_4.3 | | `mod_auth_openidc-debugsource` | Red Hat:rhel_e4s:9.4::appstream | All versions | 0:2.4.9.4-4.el9_4.3 | | `mod_auth_openidc` | Red Hat:rhel_els:7 | All versions | 0:1.8.8-9.el7_9.2 | | `mod_auth_openidc-debuginfo` | Red Hat:rhel_els:7 | All versions | 0:1.8.8-9.el7_9.2 | ## How do I fix CVE-2026-54789? Upgrade to a fixed version. ## Is CVE-2026-54789 being exploited? There is no known exploitation of CVE-2026-54789 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-54789 and fix it if it is affected. What it is: CVE-2026-54789 is a high-severity memory corruption vulnerability in mod_auth_openidc, published on 21 Aug 2026. 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-2026-54789 in the wild and no public exploit code. Affected product: mod_auth_openidc. No package-level version data is available, so check the vendor advisory linked from the reference page. 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-2026-54789/ (Markdown: https://insights.sbomify.com/CVE-2026-54789/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54789 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54789 - OSV: https://osv.dev/vulnerability/CVE-2026-54789 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-54789/ Summaries are generated and may contain mistakes; the official description above is the record.