CVE-2026-59396

MEDIUMCVSS 4.9/10EPSS 0.29%

Last modified

CVE-2026-59396 is a medium-severity vulnerability rated 4.9/10 on the CVSS scale. A denial-of-service vulnerability exists in UAA's private_key_jwt client-authentication mechanism. When UAA retrieves a remote JWKS URI, it caches the response. EPSS estimates a 0.29% chance of exploitation in the next 30 days.

Description

A denial-of-service vulnerability exists in UAA's private_key_jwt client-authentication mechanism. When UAA retrieves a remote JWKS URI, it caches the response. Invalid authentication attempts can trigger full deserialization of this cached data. An attacker with prerequisites (write access to clients or a compromised endpoint) can send anonymous requests that force repeated parsing of large cached objects, causing excessive CPU usage and potential Java heap exhaustion via OutOfMemoryError, resulting in service unavailability.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
Cloud FoundryUAA>= 76.23.0, < 79.9.0
Cloud Foundrycf-deployment< 60.11.0

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-59396?
A denial-of-service vulnerability exists in UAA's private_key_jwt client-authentication mechanism. When UAA retrieves a remote JWKS URI, it caches the response. Invalid authentication attempts can trigger full deserialization of this cached data. An attacker with prerequisites (write access to clients or a compromised endpoint) can send anonymous requests that force repeated parsing of large cached objects, causing excessive CPU usage and potential Java heap exhaustion via OutOfMemoryError, resulting in service unavailability.
How severe is CVE-2026-59396?
CVE-2026-59396 has a CVSS score of 4.9/10 (MEDIUM severity). The EPSS model estimates a 0.29% probability of exploitation in the next 30 days.
How do I fix CVE-2026-59396?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST