{"schemaVersion":3,"id":"CVE-2026-41059","aliases":["GHSA-pxq7-h93f-9jrg","BIT-oauth2-proxy-2026-41059","GO-2026-5559"],"status":"published","duplicateOf":null,"title":null,"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.","dates":{"published":"2026-04-21T23:17:46.743Z","modified":"2026-04-22T13:13:50.227Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":8.2,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","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","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Go","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","exploitability":10,"impact":7,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"NVD","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","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00432,"percentile":0.3643,"severity":"low","asOf":"2026-10-21T00:00:00.000Z","change":{"pp":0.15700000000000003,"baselineDate":"2026-09-21T00:00:00.000Z","baselineScore":0.00275},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00432,"percentile":0.3643}],"last30":[{"date":"2026-09-21T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00275,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00432,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00432,"percentile":0.3643}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-288","name":"Authentication Bypass Using an Alternate Path or Channel","description":"The product requires authentication, but the product has an alternate path or channel that does not require authentication.","type":"weakness","status":"Incomplete","abstraction":"Base","likelihoodOfExploit":null,"url":"https://cwe.mitre.org/data/definitions/288.html"}],"affected":[{"vendor":"github.com/oauth2-proxy","product":"oauth2-proxy","name":"github.com/oauth2-proxy/oauth2-proxy","label":"oauth2-proxy","ecosystem":"Go","cpePart":null,"purl":"pkg:golang/github.com/oauth2-proxy/oauth2-proxy","purlType":"golang","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"github.com/oauth2-proxy/oauth2-proxy","product":"v7","name":"github.com/oauth2-proxy/oauth2-proxy/v7","label":"v7","ecosystem":"Go","cpePart":null,"purl":"pkg:golang/github.com/oauth2-proxy/oauth2-proxy/v7","purlType":"golang","versions":[{"text":"≥ 7.5.0, < 7.15.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 7.5.0, < 7.15.2","eol":null,"hubHref":null},{"vendor":"oauth2_proxy_project","product":"oauth2_proxy","name":"oauth2 proxy","label":"oauth2_proxy","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 7.5.0, < 7.15.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 7.5.0, < 7.15.2","eol":null,"hubHref":"/vendor/oauth2_proxy_project/oauth2_proxy"},{"vendor":"oauth2-proxy","product":"oauth2-proxy","name":"oauth2-proxy","label":"oauth2-proxy","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 7.5.0, < 7.15.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 7.5.0, < 7.15.2","eol":null,"hubHref":"/vendor/oauth2-proxy/oauth2-proxy"}],"affectedCount":4,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-pxq7-h93f-9jrg","label":"github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-pxq7-h93f-9jrg","hostname":"github.com","tags":["X Refsource CONFIRM","WEB","Advisory","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41059","label":"nvd.nist.gov/vuln/detail/CVE-2026-41059","hostname":"nvd.nist.gov","tags":["Advisory"]},{"url":"https://github.com/oauth2-proxy/oauth2-proxy","label":"github.com/oauth2-proxy/oauth2-proxy","hostname":"github.com","tags":["PACKAGE"]}],"lineage":{"upstream":[],"downstream":["OPENSUSE-SU-2026:21483-1"],"duplicates":[],"related":["OPENSUSE-SU-2026:21483-1"]},"timeline":[{"kind":"published","date":"2026-04-21T23:17:46.743Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-04-22T13:13:50.227Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":33,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T23:56:08.357Z","stale":false,"partial":false}}