What’s Vulnerable › Vulnerabilities

CVE-2026-59354: Spring Security OAuth2 Authorization Server: Insufficient validation of Dynamic Client Registration metadata

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-27 · updated 2026-09-01
• Weakness: CWE-20

Description

In versions of Spring Security's OAuth2 Authorization Server module 7.0.0 through 7.0.4, when Dynamic Client Registration is explicitly enabled, the registration endpoint performs insufficient validation of certain client metadata fields supplied by the registering client. An attacker who possesses a valid Initial Access Token can register a malicious client with crafted metadata, which, depending on server configuration and how the metadata is later rendered or used, may result in Stored Cross-Site Scripting (XSS), Privilege Escalation, or Server-Side Request Forgery (SSRF).

Affected products

• Spring Security: from 7.0.0 before 7.0.5 — fixed in 7.0.5
• Spring Security: from 7.0.0 through 7.0.4

How to fix

Upgrade to a fixed version: Spring Security 7.0.5. Check the vendor advisory for mitigations.

References

• https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N&version=3.1
• https://spring.io/security/cve-2026-59354

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