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.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
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
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 | 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 |
4 more packages
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 include Vmware Spring Security.
How do I fix CVE-2026-47838?
Upgrade org.springframework.security:spring-security-web to 6.5.11 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
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 Authorization Bypass in Spring Security
- CVE-2026-59354 Spring Security OAuth2 Authorization Server: Insufficient validation of Dynamic Client Registration metadata
- CVE-2026-59270 Spring Security embedded UnboundID LDAP server exposes well-known administrative bind DN on all network interfaces
- CVE-2026-22732 Under Some Conditions Spring Security HTTP Headers Are not Written
- CVE-2023-34034 Access Control Bypass in Spring Security
Sources
Also known as CLEANSTART-2026-AF22825, CLEANSTART-2026-DX76026, CLEANSTART-2026-ML93784, CLEANSTART-2026-OE45084, CLSA-2026-1782781163, CLSA-2026-1783991058 and 13 more.