Spring Security: Improper Authentication
CVE-2026-47838 is a high-severity improper authentication vulnerability in Spring Security from Spring, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 5.7.25, 5.8.27, 6.3.18 as the first without the flaw, so updating Spring Security to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Spring Security to 5.7.25 or 5.8.27 or 6.3.18 or 6.4.18, whichever matches your release line, or a later version.
- Read the advisory on spring.io for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Spring | Spring Security | 5.7.0 up to, but not including, 5.7.25; 5.8.0 up to, but not including, 5.8.27; 6.3.0 up to, but not including, 6.3.18; 6.4.0 up to, but not including, 6.4.18; 6.5.0 up to, but not including, 6.5.10.2 | 5.7.25, 5.8.27, 6.3.18, 6.4.18, 6.5.10.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.8 | Medium | CNA (vmware.com) |
| CVSS 3.1 | 8.1 | High | NVD |
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Spring Security
- 9.1 Critical severity
- 7.4 High severity
- 7.4 High severity
- 7.2 High severity
- 7.5 High severity
- 7.5 High severity
Recent Improper Authentication vulnerabilities
- 8.3 High severity
- 7.4 High severity
- 7.3 High severity
- 9.3 Critical severity
- 7.0 High severity
- 9.8 Critical severity
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