CVE-2026-47838: Unauthorized User Impersonation when Using X.509 Client Certificates
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.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-47838?
The severity of CVE-2026-47838 is rated as medium with a score of 6.8.
How do I fix CVE-2026-47838?
To fix CVE-2026-47838, you should upgrade to the latest version of Spring Security where this vulnerability has been addressed.
What impact does CVE-2026-47838 have on my system?
CVE-2026-47838 allows unauthorized user impersonation due to improper handling of malformed X.509 certificate CN values.
Who is affected by CVE-2026-47838?
Users of Spring Security version 5.7.0 and potentially other affected versions are at risk of CVE-2026-47838.
What does CVE-2026-47838 exploit?
CVE-2026-47838 exploits the SubjectDnX509PrincipalExtractor's failure to correctly process certain malformed X.509 certificate CN values.