Unauthorized User Impersonation when Using X.509 Client Certificates
CVE-2026-47838

6.8MEDIUM

Key Information:

Vendor

Spring

Status
Spring Security
Vendor
CVE Published:
9 June 2026

What is CVE-2026-47838?

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 Version(s)

Spring Security 5.7.0 < 5.7.25

Spring Security 5.8.0 < 5.8.27

Spring Security 6.3.0 < 6.3.18

References

https://spring.io/security/cve-2026-47838

CVSS V3.1

Score:
6.8
Severity:
MEDIUM
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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