{"schemaVersion":3,"id":"CVE-2020-4037","aliases":["GHSA-5m6c-jp6f-2vcv","BIT-oauth2-proxy-2020-4037"],"status":"published","duplicateOf":null,"title":null,"description":"In OAuth2 Proxy from version 5.1.1 and less than version 6.0.0, users can provide a redirect address for the proxy to send the authenticated user to at the end of the authentication flow. This is expected to be the original URL that the user was trying to access. This redirect URL is checked within the proxy and validated before redirecting the user to prevent malicious actors providing redirects to potentially harmful sites. This has been fixed in version 6.0.0.","dates":{"published":"2020-06-29T19:45:13.000Z","modified":"2024-08-04T07:52:20.759Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":5.8,"severity":"medium","version":"2.0","versionLabel":"v2.0","source":"NVD","vector":"AV:N/AC:M/Au:N/C:P/I:P/A:N","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":4.3,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Go","score":4.3,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N","exploitability":7.2,"impact":2.3,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":5.4,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N","exploitability":null,"impact":null,"computed":false},{"version":"2.0","versionLabel":"v2.0","source":"NVD","score":5.8,"severity":"medium","vector":"AV:N/AC:M/Au:N/C:P/I:P/A:N","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00896,"percentile":0.59104,"severity":"low","asOf":"2026-10-21T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-21T00:00:00.000Z","baselineScore":0.00896},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00896,"percentile":0.59104}],"last30":[{"date":"2026-09-21T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00896,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00896,"percentile":0.59104}]},"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-601","name":"URL Redirection to Untrusted Site ('Open Redirect')","description":"The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.","type":"weakness","status":"Draft","abstraction":"Base","likelihoodOfExploit":"Low","url":"https://cwe.mitre.org/data/definitions/601.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":"≥ 5.1.1, < 6.0.0","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 5.1.1, < 6.0.0","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":"≥ 5.1.1, < 6.0.0","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 5.1.1, < 6.0.0","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":"≥ 5.1.1, < 6.0.0","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 5.1.1, < 6.0.0","eol":null,"hubHref":"/vendor/oauth2_proxy/oauth2_proxy"}],"affectedCount":3,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-5m6c-jp6f-2vcv","label":"github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-5m6c-jp6f-2vcv","hostname":"github.com","tags":["X Refsource CONFIRM","WEB","Third Party Advisory"]},{"url":"https://github.com/oauth2-proxy/oauth2-proxy/commit/ee5662e0f5001d76ec76562bb605abbd07c266a2","label":"github.com/oauth2-proxy/oauth2-proxy/commit/ee5662e0f5001d76ec76562bb605abbd07c266a2","hostname":"github.com","tags":["X Refsource MISC","WEB","Patch","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-4037","label":"nvd.nist.gov/vuln/detail/CVE-2020-4037","hostname":"nvd.nist.gov","tags":["Advisory"]},{"url":"https://github.com/oauth2-proxy/oauth2-proxy/releases/tag/v6.0.0","label":"github.com/oauth2-proxy/oauth2-proxy/releases/tag/v6.0.0","hostname":"github.com","tags":["WEB"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2020-06-29T19:45:13.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2024-08-04T07:52:20.759Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":23,"level":"low","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T17:38:06.265Z","stale":false,"partial":false}}