{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-40575", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-04-14T13:24:29.475Z", "datePublished": "2026-04-21T23:20:30.486Z", "dateUpdated": "2026-04-21T23:20:30.486Z"}, "containers": {"cna": {"title": "OAuth2 Proxy has an Authentication Bypass via X-Forwarded-Uri Header Spoofing", "problemTypes": [{"descriptions": [{"cweId": "CWE-290", "lang": "en", "description": "CWE-290: Authentication Bypass by Spoofing", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 9.1, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}}], "references": [{"name": "https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-7x63-xv5r-3p2x", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-7x63-xv5r-3p2x"}], "affected": [{"vendor": "oauth2-proxy", "product": "oauth2-proxy", "versions": [{"version": ">= 7.5.0, < 7.15.2", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-04-21T23:20:30.486Z"}, "descriptions": [{"lang": "en", "value": "OAuth2 Proxy is a reverse proxy that provides authentication using OAuth2 providers. Versions 7.5.0 through 7.15.1 may trust a client-supplied `X-Forwarded-Uri` header when `--reverse-proxy` is enabled and `--skip-auth-regex` or `--skip-auth-route` is configured. An attacker can spoof this header so OAuth2 Proxy evaluates authentication and skip-auth rules against a different path than the one actually sent to the upstream application. This can result in an unauthenticated remote attacker bypassing authentication and accessing protected routes without a valid session. Impacted users are deployments that run oauth2-proxy with `--reverse-proxy` enabled and configure at least one `--skip-auth-regex` or `--skip-auth-route` rule. This issue is patched in `v7.15.2`. Some workarounds are available for those who cannot upgrade immediately. Strip any client-provided `X-Forwarded-Uri` header at the reverse proxy or load balancer level; explicitly overwrite `X-Forwarded-Uri` with the actual request URI before forwarding requests to OAuth2 Proxy; restrict direct client access to OAuth2 Proxy so it can only be reached through a trusted reverse proxy; and/or remove or narrow `--skip-auth-regex` / `--skip-auth-route` rules where possible. For nginx-based deployments, ensure `X-Forwarded-Uri` is set by nginx and not passed through from the client."}], "source": {"advisory": "GHSA-7x63-xv5r-3p2x", "discovery": "UNKNOWN"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "OAuth2 Proxy is a reverse proxy that provides authentication using OAuth2 providers. Versions 7.5.0 through 7.15.1 may trust a client-supplied `X-Forwarded-Uri` header when `--reverse-proxy` is enabled and `--skip-auth-regex` or `--skip-auth-route` is configured. An attacker can spoof this header so OAuth2 Proxy evaluates authentication and skip-auth rules against a different path than the one actually sent to the upstream application. This can result in an unauthenticated remote attacker bypassing authentication and accessing protected routes without a valid session. Impacted users are deployments that run oauth2-proxy with `--reverse-proxy` enabled and configure at least one `--skip-auth-regex` or `--skip-auth-route` rule. This issue is patched in `v7.15.2`. Some workarounds are available for those who cannot upgrade immediately. Strip any client-provided `X-Forwarded-Uri` header at the reverse proxy or load balancer level; explicitly overwrite `X-Forwarded-Uri` with the actual request URI before forwarding requests to OAuth2 Proxy; restrict direct client access to OAuth2 Proxy so it can only be reached through a trusted reverse proxy; and/or remove or narrow `--skip-auth-regex` / `--skip-auth-route` rules where possible. For nginx-based deployments, ensure `X-Forwarded-Uri` is set by nginx and not passed through from the client."}], "id": "CVE-2026-40575", "lastModified": "2026-04-22T00:16:27.817", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 9.1, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.2, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-04-22T00:16:27.817", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-7x63-xv5r-3p2x"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-290"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"analysis": {"en": {"generated_at": "2026-04-22T02:10:49.574322+00:00", "value": {"mitigation_remediation": ["Apply the available patch to upgrade to oauth2\u2011proxy v7.15.2 or later.", "Configure the reverse proxy or load balancer so that it does not forward client\u2011supplied X-Forwarded-Uri headers; instead, overwrite the header with the actual request URI before forwarding to OAuth2 Proxy.", "Remove or narrow any --skip-auth-regex or --skip-auth-route rules so that they match only the intended exempt paths.", "Restrict direct client access to the OAuth2 Proxy so that it is only reachable through a trusted reverse proxy in the infrastructure."], "summary": {"action": "Immediate Patch", "impact": "Authentication Bypass"}, "threat_synthesis": {"affected_systems": "Versions 7.5.0 through 7.15.1 of the oauth2\u2011proxy project that run with the --reverse-proxy flag and define at least one --skip-auth-regex or --skip-auth-route rule are affected. Deployments using these settings are at risk.", "description_and_impact": "OAuth2 Proxy may accept a client\u2011supplied X-Forwarded-Uri header when reverse proxy mode is enabled and skip\u2011auth rules are active. This allows an attacker to spoof the header so the proxy evaluates authentication and skip\u2011auth logic against a different path than the one actually requested, thereby bypassing authentication and gaining access to protected resources without a valid session.", "risk_and_exploitability": "The vulnerability carries a CVSS score of 9.1, indicating a high severity authentication bypass. No EPSS score is currently available, but the absence of a KEV listing does not reduce the risk; attackers who can reach the proxy instance can send crafted HTTP requests to manipulate the X-Forwarded-Uri header, escalating privilege and accessing restricted content. Exploitation requires only the ability to send requests to OAuth2 Proxy, which is common in web\u2011based deployments."}}}}, "created": "2026-04-22T02:15:05.403034+00:00", "updated": "2026-04-22T02:15:05.403045+00:00", "vendors": []}