Technical impact
Improper handling of case sensitivity in the identity zone authorization check in Cloud Foundry UAA allows a remote authenticated attacker holding only the zones.write authority to bypass the intended restriction that this authority does not grant access to the privileged uaa (system) identity zone. By referring to the zone identifier in a non-lowercase form (e.g. UAA) in the request path and body, the authorization layer performs a case-sensitive comparison against the system zone identifier while the underlying MySQL persistence layer resolves identifiers case-insensitively. This incorrect authorization permits the attacker to overwrite the system zone's JWT signing key with attacker-controlled key material, forge JWTs claiming the admin client and administrator scopes, and fully compromise UAA and any Cloud Foundry deployment that trusts it.
Affected Systems
Cloud Foundry UAA, Cloud Foundry cf-deployment with MySQL backends using the default case-insensitive collation. PostgreSQL and HSQLDB backends are not affected.
Risk and Exploitability
The CVSS vector scores 8.7, indicating high severity, and the lack of an EPSS score suggests insufficient data on exploitation likelihood. Although the vulnerability is not listed in the CISA KEV catalog, the ability for an authenticated attacker to control the JWT signing key and forge privileged tokens makes this a potent threat. Attackers must possess the zones.write authority and the backend must be MySQL; the attack vector is a remote HTTP request manipulating the zone identifier’s case.
