{"id":"CVE-2026-75833","title":"The Grav API plugin (getgrav/grav-plugin-api, bundled with Grav 2.0's admin-next/API stack) before version 1.0.14 contains an open redirect weakness in SsoController::sanitizeReturnTo()","summary":"The Grav API plugin (getgrav/grav-plugin-api, bundled with Grav 2.0's admin-next/API stack) before version 1.0.14 contains an open redirect weakness in SsoController::sanitizeReturnTo(). The function rejects a literal '//' prefix but doe…","severity":"medium","cvss":4.2,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N","cwe":["CWE-601"],"published":"2026-08-18","updated":"2026-09-08","sourceUpdated":"2026-09-08T20:32:39.347","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-75833","references":[{"url":"https://github.com/getgrav/grav/security/advisories/GHSA-x72c-4jc4-8rh6","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/grav-api-plugin-open-redirect-via-backslash-bypass","label":"disclosure@vulncheck.com"}],"tags":["nvd"],"epss":0.00194,"epssPercentile":0.09353,"ingestedAt":"2026-09-08T21:11:12.279Z","slug":"CVE-2026-75833","body":"## Overview\n\nThe Grav API plugin (getgrav/grav-plugin-api, bundled with Grav 2.0's admin-next/API stack) before version 1.0.14 contains an open redirect weakness in SsoController::sanitizeReturnTo(). The function rejects a literal '//' prefix but does not account for browsers normalizing backslashes to slashes in special (http/https) schemes, so a returnTo value such as '/\\evil.com' passes the guard and is later resolved by the browser as the protocol-relative URL '//evil.com'. Following a legitimate OAuth login flow, an attacker-supplied returnTo parameter could redirect an authenticated victim to an attacker-controlled site for post-login phishing. Full browser-side exploitability depends on the admin-next SPA's client-side oauth-callback handler and was not independently verified by the reporter.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":23,"depthScoreParts":{"impact":23.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}