{"api_version":"1","generated_at":"2026-04-22T04:15:13+00:00","cve":"CVE-2026-41059","urls":{"html":"https://cve.report/CVE-2026-41059","api":"https://cve.report/api/cve/CVE-2026-41059.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-41059","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-41059"},"summary":{"title":"OAuth2 Proxy has an Authentication Bypass via Fragment Confusion in skip_auth_routes and skip_auth_regex","description":"OAuth2 Proxy is a reverse proxy that provides authentication using OAuth2 providers. Versions 7.5.0 through 7.15.1 have a configuration-dependent authentication bypass. Deployments are affected when all of the following are true: Use of `skip_auth_routes` or the legacy `skip_auth_regex`; use of patterns that can be widened by attacker-controlled suffixes, such as `^/foo/.*/bar$` causing potential exposure of `/foo/secret`; and protected upstream applications that interpret `#` as a fragment delimiter or otherwise route the request to the protected base path. In deployments that rely on these settings, an unauthenticated attacker can send a crafted request containing a number sign in the path, including the browser-safe encoded form `%23`, so that OAuth2 Proxy matches a public allowlist rule while the backend serves a protected resource. Deployments that do not use these skip-auth options, or that only allow exact public paths with tightly scoped method and path rules, are not affected. A fix has been implemented in version 7.15.2 to normalize request paths more conservatively before skip-auth matching so fragment content does not influence allowlist decisions. Users who cannot upgrade immediately can reduce exposure by tightening or removing `skip_auth_routes` and `skip_auth_regex` rules, especially patterns that use broad wildcards across path segments. Recommended mitigations include replacing broad rules with exact, anchored public paths and explicit HTTP methods; rejecting requests whose path contains `%23` or `#` at the ingress, load balancer, or WAF level; and/or avoiding placing sensitive application paths behind broad `skip_auth_routes` rules.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-04-22 00:16:27","updated_at":"2026-04-22 00:16:27"},"problem_types":["CWE-288","CWE-288 CWE-288: Authentication Bypass Using an Alternate Path or Channel"],"metrics":[{"version":"3.1","source":"security-advisories@github.com","type":"Secondary","score":"8.2","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N","baseScore":8.2,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"LOW","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.2","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N","data":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":8.2,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N","version":"3.1"}}],"references":[{"url":"https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-pxq7-h93f-9jrg","name":"https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-pxq7-h93f-9jrg","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-41059","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41059","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"oauth2-proxy","product":"oauth2-proxy","version":"affected >= 7.5.0, < 7.15.2","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"product":"oauth2-proxy","vendor":"oauth2-proxy","versions":[{"status":"affected","version":">= 7.5.0, < 7.15.2"}]}],"descriptions":[{"lang":"en","value":"OAuth2 Proxy is a reverse proxy that provides authentication using OAuth2 providers. 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A fix has been implemented in version 7.15.2 to normalize request paths more conservatively before skip-auth matching so fragment content does not influence allowlist decisions. Users who cannot upgrade immediately can reduce exposure by tightening or removing `skip_auth_routes` and `skip_auth_regex` rules, especially patterns that use broad wildcards across path segments. Recommended mitigations include replacing broad rules with exact, anchored public paths and explicit HTTP methods; rejecting requests whose path contains `%23` or `#` at the ingress, load balancer, or WAF level; and/or avoiding placing sensitive application paths behind broad `skip_auth_routes` rules."}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":8.2,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-288","description":"CWE-288: Authentication Bypass Using an Alternate Path or Channel","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-04-21T23:17:46.743Z","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M"},"references":[{"name":"https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-pxq7-h93f-9jrg","tags":["x_refsource_CONFIRM"],"url":"https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-pxq7-h93f-9jrg"}],"source":{"advisory":"GHSA-pxq7-h93f-9jrg","discovery":"UNKNOWN"},"title":"OAuth2 Proxy has an Authentication Bypass via Fragment Confusion in skip_auth_routes and skip_auth_regex"}},"cveMetadata":{"assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","assignerShortName":"GitHub_M","cveId":"CVE-2026-41059","datePublished":"2026-04-21T23:17:46.743Z","dateReserved":"2026-04-16T16:43:03.173Z","dateUpdated":"2026-04-21T23:17:46.743Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-04-22 00:16:27","lastModifiedDate":"2026-04-22 00:16:27","problem_types":["CWE-288","CWE-288 CWE-288: Authentication Bypass Using an Alternate Path or Channel"],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N","baseScore":8.2,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"LOW","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":4.2}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"41059","Ordinal":"1","Title":"OAuth2 Proxy has an Authentication Bypass via Fragment Confusion","CVE":"CVE-2026-41059","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"41059","Ordinal":"1","NoteData":"OAuth2 Proxy is a reverse proxy that provides authentication using OAuth2 providers. Versions 7.5.0 through 7.15.1 have a configuration-dependent authentication bypass. Deployments are affected when all of the following are true: Use of `skip_auth_routes` or the legacy `skip_auth_regex`; use of patterns that can be widened by attacker-controlled suffixes, such as `^/foo/.*/bar$` causing potential exposure of `/foo/secret`; and protected upstream applications that interpret `#` as a fragment delimiter or otherwise route the request to the protected base path. In deployments that rely on these settings, an unauthenticated attacker can send a crafted request containing a number sign in the path, including the browser-safe encoded form `%23`, so that OAuth2 Proxy matches a public allowlist rule while the backend serves a protected resource. Deployments that do not use these skip-auth options, or that only allow exact public paths with tightly scoped method and path rules, are not affected. A fix has been implemented in version 7.15.2 to normalize request paths more conservatively before skip-auth matching so fragment content does not influence allowlist decisions. Users who cannot upgrade immediately can reduce exposure by tightening or removing `skip_auth_routes` and `skip_auth_regex` rules, especially patterns that use broad wildcards across path segments. Recommended mitigations include replacing broad rules with exact, anchored public paths and explicit HTTP methods; rejecting requests whose path contains `%23` or `#` at the ingress, load balancer, or WAF level; and/or avoiding placing sensitive application paths behind broad `skip_auth_routes` rules.","Type":"Description","Title":"OAuth2 Proxy has an Authentication Bypass via Fragment Confusion"}]}}}