{"cve":"CVE-2026-58399","nvd":{"published":"2026-07-01T15:17:11.377","modified":"2026-10-25T17:10:00.197","status":"Deferred","description":"@acastellon/auth is an authentication control system for microservices. Versions prior to 2.3.0 appear to allow an unauthenticated authentication bypass in validateToken() through spoofable auth-user and Host request headers. The validateToken middleware contains a service-to-service bypass for auth-user: service-brother when req.get('host').startsWith(getHostName()). Both values involved in the check can be influenced by an unauthenticated HTTP client: auth-user is a request header, and Host is also client-controlled. As a result, a remote unauthenticated attacker can send a request with crafted headers and bypass token validation before the normal legacy/JWT/OIDC validation logic runs. A fix has been implemented in v2.3.0.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","score":8.7},"cvss_v3":null,"cwes":["CWE-287"],"references":["https://github.com/antonio-castellon/module-auth/issues/6","https://github.com/antonio-castellon/module-auth/security/advisories/GHSA-gfj5-979r-92pw","https://www.npmjs.com/package/@acastellon/auth/v/2.3.0"],"products":[],"source":"nvd","synced_at":"2026-10-25T17:50:06.907763985+00:00"},"epss":{"cve":"CVE-2026-58399","score":0.00973,"percentile":0.61783,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-gfj5-979r-92pw","url":"https://osv.dev/vulnerability/GHSA-gfj5-979r-92pw","summary":"@acastellon/auth: Authentication bypass via spoofable headers in validateToken()","modified":"2026-09-10T03:51:08.661430056Z","packages":[{"ecosystem":"npm","name":"@acastellon/auth","purl":"pkg:npm/%40acastellon/auth","ranges":["<2.3.0"],"fixed":["2.3.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}