# CVE-2026-47838: Unauthorized User Impersonation when Using X.509 Client Certificates > Attackers can impersonate other users via malformed X.509 certificates in Spring Security, requiring X.509 authentication to be enabled. - **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/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:** 9 Jun 2026 - **Updated:** 30 Jun 2026 - **Also known as:** CLEANSTART-2026-AF22825, CLEANSTART-2026-DX76026, CLEANSTART-2026-ML93784, CLEANSTART-2026-OE45084, CLSA-2026-1782781163, CLSA-2026-1783991058, CLSA-2026-1785204414, CLSA-2026-1787661459, ECHO-52e5-784b-5fb7, GHSA-293q-567p-wmwq, MINI-c936-hp2p-5hgw, MINI-ccxp-593v-332r, MINI-g2h2-phc2-cg78, MINI-h6w7-2392-vhvf, MINI-hxv3-pmjv-5987, MINI-qqwc-vr59-w75p, MINI-qxc9-6m2c-5m46, MINI-x469-fvvq-p5q6, ROOT-APP-MAVEN-CVE-2026-47838 ## What is CVE-2026-47838? CVE-2026-47838 is a medium-severity authentication bypass vulnerability in Spring Security, published on 9 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim. ### Official description SubjectDnX509PrincipalExtractor does not correctly handle certain malformed X.509 certificate CN values, which can lead to reading the wrong value for the username. In a carefully crafted certificate, this can lead to an attacker impersonating another user. Affected versions: Spring Security 5.7.0 through 5.7.24; 5.8.0 through 5.8.26; 6.3.0 through 6.3.17; 6.4.0 through 6.4.17; 6.5.0 through 6.5.10. Weakness: CWE-287 (Improper Authentication) ## Which versions are affected by CVE-2026-47838? 10 open source packages ship an affected version, including org.springframework.security:spring-security-web. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `org.springframework.security:spring-security-web` | Maven | All versions to 5.7.14 | None | | `org.springframework.security:spring-security-web` | Maven | All versions to 5.7.14 | None | | `org.springframework.security:spring-security-web` | Maven | From 5.8.0 to 5.8.16 | None | | `org.springframework.security:spring-security-web` | Maven | From 5.8.0 to 5.8.16 | None | | `org.springframework.security:spring-security-web` | Maven | From 6.0.0 to 6.3.10 | None | | `org.springframework.security:spring-security-web` | Maven | From 6.0.0 to 6.3.10 | None | | `org.springframework.security:spring-security-web` | Maven | From 6.4.0 to 6.4.13 | None | | `org.springframework.security:spring-security-web` | Maven | From 6.4.0 to 6.4.13 | None | | `org.springframework.security:spring-security-web` | Maven | From 6.5.0 | 6.5.11 | | `org.springframework.security:spring-security-web` | Maven | From 6.5.0 | 6.5.11 | Products: Vmware Spring Security. ## How do I fix CVE-2026-47838? Upgrade org.springframework.security:spring-security-web to 6.5.11 or later. ## Is CVE-2026-47838 being exploited? There is no known exploitation of CVE-2026-47838 in the wild and no public exploit code. ## Other vulnerabilities in Spring Security - [CVE-2014-3527](https://insights.sbomify.com/CVE-2014-3527/): Authorization Bypass in Spring Security (critical 9.8) - [CVE-2026-59354](https://insights.sbomify.com/CVE-2026-59354/): Spring Security OAuth2 Authorization Server: Insufficient validation of Dynamic Client Registration metadata (critical 9.6) - [CVE-2026-59270](https://insights.sbomify.com/CVE-2026-59270/): Spring Security embedded UnboundID LDAP server exposes well-known administrative bind DN on all network interfaces (critical 9.4) - [CVE-2026-22732](https://insights.sbomify.com/CVE-2026-22732/): Under Some Conditions Spring Security HTTP Headers Are not Written (critical 9.1) - [CVE-2023-34034](https://insights.sbomify.com/CVE-2023-34034/): Access Control Bypass in Spring Security (critical 9.1) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-47838 and fix it if it is affected. What it is: CVE-2026-47838 is a medium-severity authentication bypass vulnerability in Spring Security, published on 9 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-47838 in the wild and no public exploit code. Affected packages and fixed versions: - org.springframework.security:spring-security-web (Maven): affected all versions up to 5.7.14; no fix listed - org.springframework.security:spring-security-web (Maven): affected all versions up to 5.7.14; no fix listed - org.springframework.security:spring-security-web (Maven): affected from 5.8.0 up to 5.8.16; no fix listed - org.springframework.security:spring-security-web (Maven): affected from 5.8.0 up to 5.8.16; no fix listed - org.springframework.security:spring-security-web (Maven): affected from 6.0.0 up to 6.3.10; no fix listed - org.springframework.security:spring-security-web (Maven): affected from 6.0.0 up to 6.3.10; no fix listed - org.springframework.security:spring-security-web (Maven): affected from 6.4.0 up to 6.4.13; no fix listed - org.springframework.security:spring-security-web (Maven): affected from 6.4.0 up to 6.4.13; no fix listed - org.springframework.security:spring-security-web (Maven): affected from 6.5.0; fixed in 6.5.11 - org.springframework.security:spring-security-web (Maven): affected from 6.5.0; fixed in 6.5.11 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-2026-47838/ (Markdown: https://insights.sbomify.com/CVE-2026-47838/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-47838 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-47838 - OSV: https://osv.dev/vulnerability/CVE-2026-47838 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-47838/ Summaries are generated and may contain mistakes; the official description above is the record.