{"id":"CVE-2026-59358","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-59358","generatedAt":"2026-10-28T00:57:19.727Z","title":"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…","description":"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.\n\n\n\nUAA’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.\n\n\n\nExploitation 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.","published":"2026-10-06T07:16:59.000Z","lastModified":"2026-10-06T16:00:37.000Z","status":"Awaiting Analysis","sourceIdentifier":"security@vmware.com","cvss":{"version":"4.0","score":7.6,"severity":"HIGH","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-287"],"affected":[],"epss":{"score":0.00413,"percentile":0.35302,"date":"2026-10-26","history":[{"date":"2026-10-06","score":0.00346,"percentile":0.25917}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.41%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-06T07:16:59.000Z","detail":{"score":"7.6","severity":"HIGH","publishedAt":"2026-10-06T07:16:59.460Z"},"summary":"New CVE, high severity (CVSS 7.6)."}],"references":[{"url":"https://www.cloudfoundry.org/blog/cve-2026-59358-uaa-oauth-token-endpoint-vulnerability-allows-user-access-token-reuse-for-client_credentials-grant-type/","source":"security@vmware.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-59358","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}