CVE-2026-47838
Spring Security Vulnerable to Unauthorized User Impersonation when Using X.509 Client Certificates
Description
In Spring Security Web, `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. `SubjectDnX509PrincipalExtractor` is deprecated by this CVE and replaced with `SubjectX500PrincipalExtractor`. As part of updating, you should also migrate to `SubjectX500PrincipalExtractor`. Affected versions: Spring Security Enterprise 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. OSS 6.5.0 through 6.5.10.
How to fix CVE-2026-47838
To remediate CVE-2026-47838, upgrade the affected package to a fixed version below.
- —upgrade to 6.5.11 or later
Is CVE-2026-47838 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- >= 6.5.0, < 6.5.11
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.8 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N |