{"cve":"CVE-2026-40574","nvd":{"published":"2026-04-21T17:16:55.730","modified":"2026-06-17T10:45:28.563","status":"Analyzed","description":"OAuth2 Proxy is a reverse proxy that provides authentication using OAuth2 providers. Prior to 7.15.2, an authorization bypass exists in OAuth2 Proxy as part of the email_domain enforcement option. An attacker may be able to authenticate with an email claim such as attacker@evil.com@company.com and satisfy an allowed domain check for company.com, even though the claim is not a valid email address. The issue ONLY affects deployments that rely on email_domain restrictions and accept email claim values from identity providers or claim mappings that do not strictly enforce normal email syntax. This vulnerability is fixed in 7.15.2.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","score":6.8},"cwes":["CWE-863"],"references":["https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-c5c4-8r6x-56w3"],"products":["oauth2_proxy_project:oauth2_proxy"],"source":"nvd","synced_at":"2026-10-19T22:30:49.762551342+00:00"},"epss":{"cve":"CVE-2026-40574","score":0.00209,"percentile":0.11004,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-c5c4-8r6x-56w3","url":"https://osv.dev/vulnerability/GHSA-c5c4-8r6x-56w3","summary":"OAuth2 Proxy has an Authorization Bypass in Email Domain Validation via Malformed Multi-@ Email Claims","modified":"2026-07-21T13:56:41Z","packages":[{"ecosystem":"Go","name":"github.com/oauth2-proxy/oauth2-proxy/v7","purl":"pkg:golang/github.com/oauth2-proxy/oauth2-proxy/v7","ranges":["<7.15.2"],"fixed":["7.15.2"]}]},{"id":"GO-2026-5314","url":"https://osv.dev/vulnerability/GO-2026-5314","summary":"OAuth2 Proxy has an Authorization Bypass in Email Domain Validation via Malformed Multi-@ Email Claims in github.com/oauth2-proxy/oauth2-proxy","modified":"2026-06-25T19:56:30.792437450Z","packages":[{"ecosystem":"Go","name":"github.com/oauth2-proxy/oauth2-proxy","purl":"pkg:golang/github.com/oauth2-proxy/oauth2-proxy","ranges":["all versions"],"fixed":[]},{"ecosystem":"Go","name":"github.com/oauth2-proxy/oauth2-proxy/v7","purl":"pkg:golang/github.com/oauth2-proxy/oauth2-proxy/v7","ranges":["<7.15.2"],"fixed":["7.15.2"]}]}],"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."]}