---
id: CVE-2026-59396
title: DoS Vulnerability in UAA Related to JWKS URI Handling
summary: >-
  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 cac…
severity: medium
cvss: 4.9
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
vendor: Cloud Foundry
product: UAA
affected:
  - UAA >= 76.23.0 < 79.9.0
  - cf-deployment < 60.11.0
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-30T15:28:01.628068Z'
published: '2026-10-30'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T20:10:01.484Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-59396'
references:
  - url: >-
      https://www.cloudfoundry.org/blog/cve-2026-59396-dos-vulnerability-in-uaa-related-to-jwks-uri-handling-2/
tags:
  - cve.org
epss: 0.00287
epssPercentile: 0.21303
ingestedAt: '2026-11-05T16:24:31.455Z'
---

## Overview

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.

## Affected

- `UAA >= 76.23.0 < 79.9.0`
- `cf-deployment < 60.11.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.