# CVE-2018-16838: Auth bypass in sssd > SSSD allows all authenticated users to log in when Group Policy Objects are unreadable due to strict server-side permissions, bypassing access controls. - **Severity:** Medium 5.4 (`CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 25 Mar 2019 - **Updated:** 13 Feb 2025 - **Also known as:** DEBIAN-CVE-2018-16838, GHSA-h2vj-4wwx-54q4, MGASA-2019-0395, RHSA-2019:3651, SUSE-SU-2019:1476-1, SUSE-SU-2019:1477-1, SUSE-SU-2019:1480-1, UBUNTU-CVE-2018-16838, openSUSE-SU-2019:1589-1 ## What is CVE-2018-16838? CVE-2018-16838 is a medium-severity authentication bypass vulnerability in Redhat Enterprise Linux, published on 25 Mar 2019. Any signed-in user can exploit it over the network, with no action from the victim. ### Official description A flaw was found in sssd Group Policy Objects implementation. When the GPO is not readable by SSSD due to a too strict permission settings on the server side, SSSD will allow all authenticated users to login instead of denying access. Weakness: CWE-269 (Improper Privilege Management), CWE-284 (Improper Access Control) ## Which versions are affected by CVE-2018-16838? It affects 2 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `libipa_hbac` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libipa_hbac-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libsss_autofs` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libsss_autofs-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libsss_certmap` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libsss_certmap-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libsss_idmap` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libsss_idmap-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libsss_nss_idmap` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libsss_nss_idmap-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libsss_simpleifp` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libsss_simpleifp-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libsss_sudo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `libsss_sudo-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `python3-libipa_hbac` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `python3-libipa_hbac-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `python3-libsss_nss_idmap` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `python3-libsss_nss_idmap-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `python3-sss` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `python3-sss-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `python3-sss-murmur` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `python3-sss-murmur-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `python3-sssdconfig` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-ad` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-ad-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-client` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-client-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-common` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-common-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-common-pac` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-common-pac-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-dbus` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-dbus-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-ipa` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-ipa-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-kcm` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | | `sssd-kcm-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.2.0-19.el8 | Products: Fedoraproject Sssd, Redhat Enterprise Linux. ## How do I fix CVE-2018-16838? Apply the vendor's patch. ## Is CVE-2018-16838 being exploited? There is no known exploitation of CVE-2018-16838 in the wild and no public exploit code. ## Other vulnerabilities in Redhat Enterprise Linux - [CVE-2022-4254](https://insights.sbomify.com/CVE-2022-4254/): Other in SSSD (high 8.8) - [CVE-2012-3462](https://insights.sbomify.com/CVE-2012-3462/): Auth bypass in sssd (high 8.8) - [CVE-2026-104048](https://insights.sbomify.com/CVE-2026-104048/): Sssd: sssd: authorization bypass via cross-domain username collision in hbac evaluation (medium 6.8) - [CVE-2015-5292](https://insights.sbomify.com/CVE-2015-5292/): Denial of service in n/a (medium 6.8) - [CVE-2026-12610](https://insights.sbomify.com/CVE-2026-12610/): Sssd: use-after-free crash in sssd' 'sssd_pam' process (medium 6.4) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2018-16838 and fix it if it is affected. What it is: CVE-2018-16838 is a medium-severity authentication bypass vulnerability in Redhat Enterprise Linux, published on 25 Mar 2019. Any signed-in user can exploit it over the network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2018-16838 in the wild and no public exploit code. Affected product: Redhat Enterprise Linux. 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-2018-16838/ (Markdown: https://insights.sbomify.com/CVE-2018-16838/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2018-16838 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-16838 - OSV: https://osv.dev/vulnerability/CVE-2018-16838 --- From sbomify Insights: https://insights.sbomify.com/CVE-2018-16838/ Summaries are generated and may contain mistakes; the official description above is the record.