Spring Security X.509 CN Mismatch: SubjectDnX509PrincipalExtractor (5.7-6.5)
CVE-2026-47838 Published on June 9, 2026

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.

NVD

Vulnerability Analysis

CVE-2026-47838 is exploitable with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality and integrity, and no impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
HIGH
Privileges Required:
LOW
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
NONE

Weakness Type

What is an authentification Vulnerability?

When an actor claims to have a given identity, the software does not prove or insufficiently proves that the claim is correct.

CVE-2026-47838 has been classified to as an authentification vulnerability or weakness.


Affected Versions

Spring Security: