CVE-2026-59335 in UAA
Summary
by MITRE • 08/25/2026
Improper handling of case sensitivity (CWE-178) in the identity zone authorization check in the Identity Zone Endpoint 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 under its default collation, so the request is authorized incorrectly and is then resolved against the real system zone record. This allows 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. This issue only affects UAA deployments backed by MySQL using its default collation; PostgreSQL and HSQLDB backends are not affected.
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Analysis
by VulDB Data Team • 08/25/2026
The vulnerability identified as CWE-178 involves an improper handling of case sensitivity within the identity zone authorization logic of the Cloud Foundry User Account and Authentication (UAA) service. This flaw specifically impacts deployments utilizing a MySQL database backend configured with its default collation settings, which are inherently case-insensitive for string comparisons. The core technical failure occurs during the validation process when an authenticated user possessing only the zones.write authority attempts to access or modify resources within the privileged uaa system identity zone. Under normal security expectations, this limited authorization scope should strictly prevent any modification of the critical system zone configuration. However, because the application layer performs a case-sensitive comparison against the expected lowercase identifier while the underlying MySQL persistence layer resolves identifiers in a case-insensitive manner, a discrepancy arises that allows unauthorized access.
When an attacker constructs a request targeting the identity zone endpoint and specifies the zone identifier using non-lowercase characters, such as UAA instead of uaa, the application's authorization check fails to recognize this as a match for the restricted system zone due to its case-sensitive logic. Consequently, the authorization layer incorrectly permits the operation based on the mismatched string comparison. The request is then passed through to the database layer, where MySQL resolves the identifier regardless of case and locates the actual system zone record. This architectural misalignment between the application's security checks and the data storage engine's resolution rules effectively bypasses the intended access controls, allowing the attacker to interact with protected resources that should remain immutable under their current privilege level.
The operational impact of this vulnerability is severe, leading to a complete compromise of the UAA service and potentially any Cloud Foundry deployment that relies on it for authentication and authorization. By exploiting this case sensitivity flaw, an authenticated attacker can overwrite the system zone's JSON Web Token signing key with maliciously controlled key material. This action enables the forgery of JWTs that claim administrative privileges, including admin client status and administrator scopes. Once these forged tokens are generated, they are accepted as valid by downstream services trusting the UAA issuer, granting the attacker full control over the identity infrastructure. This level of access allows for comprehensive data exfiltration, privilege escalation across all connected applications, and persistent backdoor installation within the cloud environment.
Mitigation strategies must address both the immediate technical flaw and broader security posture improvements. The primary remediation involves upgrading to a patched version of Cloud Foundry UAA that corrects the case sensitivity handling in the identity zone authorization checks. For environments where an upgrade is not immediately feasible, administrators should consider migrating their database backend from MySQL with default collation to PostgreSQL or HSQLDB, as these alternatives do exhibit consistent behavior regarding identifier resolution and are unaffected by this specific vulnerability vector. Additionally, implementing strict input validation that normalizes case before processing requests can provide a defensive layer against such bypass attempts. Security teams should also audit existing JWT signing keys for any signs of unauthorized modification and rotate credentials immediately if compromise is suspected.
From an industry standard perspective, this incident aligns with CWE-178 regarding improper handling of case sensitivity and represents a classic example of logic flaws leading to privilege escalation. In the context of the MITRE ATT&CK framework, this vulnerability facilitates techniques associated with Tactic 06: Credential Access, specifically through the forging or manipulation of authentication credentials such as JWTs. It also touches upon Tactic 12: Defense Evasion by bypassing established authorization controls. Recognizing these mappings helps in categorizing the risk accurately and aligning remediation efforts with recognized security frameworks to ensure comprehensive protection against similar logic-based attacks in identity management systems.