CVE-2026-59358
HighCVSS 7.6Exploitation Probability (EPSS)
Low risk26th percentile - higher than 26% of all known CVEs
Summary
A vulnerability in Cloud Foundry UAA's OAuth token endpoint allows an authenticated attacker with a valid user access token to obtain a fully-privileged client_credentials token for the OAuth client that issued it, by presenting the user token as a Bearer credential on a client_credentials grant request. UAA fails to verify that the Bearer credential is actually a client credential, accepting any valid access token with a matching client_id.
Risk Assessment
An attacker can escalate from a user token (scoped only to uaa.user) to a client token with full authorities such as clients.write, enabling creation of arbitrary OAuth clients with chosen authorities. This can lead to unauthorized access and compromise of OAuth configuration within the organization.
Recommendation
Immediately update Cloud Foundry UAA to a patched version and configure OAuth clients to avoid combining public user authorization flows with the client_credentials grant on the same client_id. Additionally, restrict client authorities and monitor client_credentials requests for anomalous Bearer credentials.
Other vulnerabilities in Cloud Foundry UAA
See all- CVE-2017-4963High
An issue was discovered in Cloud Foundry affecting versions v252 and earlier, as well as UAA versions from v2.0.0 to v2.7.4.12 and from v3.0.0 to v3.11.0. UAA is vulnerable to session fixation when configured to authenticate against external SAML or OpenID Connect based identity providers.
- CVE-2017-4960High
An issue was discovered in Cloud Foundry release v247 through v252 and UAA release v3.9.0 through v3.11.0 that may lead to a denial of service attack on UAA OAuth clients.
- CVE-2016-6659High
Cloud Foundry and UAA versions before 248; UAA 2.x before 2.7.4.12, 3.x before 3.6.5, and 3.7.x through 3.9.x before 3.9.3 have a vulnerability that allows attackers to gain privileges by accessing UAA logs and subsequently running a specially crafted application that interacts with a configured SAML provider.
- CVE-2026-40965Critical
Cloud Foundry UAA versions v76.12.0 through v78.12.0 inadvertently expose EC private keys through the public /token_keys endpoint. The vulnerability affects only deployments using EC keys for JWT token signing.
- CVE-2026-59357Medium
A vulnerability in Cloud Foundry UAA (versions 4.5.0 to 79.6.0) stems from insufficient verification of data authenticity in the external OIDC login callback. It allows an authenticated UAA user to bypass the OAuth authorization-code exchange and establish an authenticated external-OIDC browser session by submitting a valid UAA JWT as the callback's id_token parameter.
- CVE-2026-59335High
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.
Original NVD description (English source)
Improper authentication (CWE-287) in the OAuth token endpoint in Cloud Foundry UAA allows a remote, authenticated attacker holding a valid user access token to obtain a fully-privileged client_credentials token for the OAuth client that issued it, by presenting the user token as an OAuth 2.0 Bearer credential on a client_credentials grant request in place of the client’s configured secret. UAA’s client_credentials handling does not verify that the Bearer credential supplied for client authentication is actually a client credential (a client secret or a valid configured client authentication method); it accepts any valid access token whose client_id matches the request. A token obtained by a normal end user through a public authorization_code + PKCE flow — scoped only to uaa.user, carrying a user_id, and recording client_auth_method=none — satisfies this check. That user token cannot itself administer OAuth clients (POST /oauth/clients correctly returns 403), but when replayed as Bearer authentication on a client_credentials request for the same client, UAA issues a new client-only token carrying the client’s full authorities, such as clients.write. An attacker can use that token to create arbitrary new OAuth clients, including clients with attacker-chosen authorities, without ever possessing the client’s actual secret. Exploitation requires a valid user access token (the attacker’s own) for a client that is configured to support both a public, user-facing authorization flow and the client_credentials grant type on the same client_id — a non-default combination. Practical impact scales with the authorities assigned to that client.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS