phpMyFAQ 4.1.3 — incomplete fix for the admin-API IDOR/privilege-escalation class

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.1.3"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "thorsten/phpmyfaq"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.1.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.1.3"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "phpmyfaq/phpmyfaq"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.1.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-832"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-26T21:23:37Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "## Advisory / Disclosure\n\n# phpMyFAQ 4.1.3 \u2014 incomplete fix for the admin-API IDOR/privilege-escalation class\n\n**Target:** thorsten/phpMyFAQ (composer: `thorsten/phpmyfaq`, `phpmyfaq/phpmyfaq`)\n**Affected:** \u003c= 4.1.3 (the 4.1.3 security fix is incomplete; siblings remain)\n**Class:** CWE-862 Missing Authorization / CWE-269 Improper Privilege Management / CWE-639 Authorization Bypass Through User-Controlled Key\n**Methodology:** M1 incomplete-fix audit (sibling-walk of the 4.1.3 fix for GHSA-xvp4-phqj-cjr3)\n**Severity:** High \u2014 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H = 8.8 (same class as the parent CVE)\n\n## Summary\n\nphpMyFAQ 4.1.3 fixed **GHSA-xvp4-phqj-cjr3** (\"IDOR Account Takeover\") by adding actor-authorization guards to `UserController::overwritePassword()`. The patch establishes a new invariant, stated in its own code comments:\n\n\u003e \"Only SuperAdmins may change other users\u0027 [attributes]. Self-service is\n\u003e always allowed.\" and \"a non-SuperAdmin must never be able to alter a\n\u003e SuperAdmin or protected account.\"\n\nThat invariant is **not enforced** on two sibling endpoints in the *same file*, which the 4.1.3 fix left **unchanged**, and which carry the identical \"user-controlled `userId` \u2192 `getUserById()` \u2192 privileged mutation\" primitive \u2014 but with a strictly more dangerous sink:\n\n| Endpoint | Route | Sink | Guard in 4.1.3 |\n|----------|-------|------|----------------|\n| `overwritePassword()` | `admin/api/user/overwrite-password` | `changePassword()` | **isSelf + isSuperAdmin + target-protection** (patched) |\n| `editUser()` | `admin/api/user/edit` | `setSuperAdmin((bool)$req.is_superadmin)` | **none** (only `userHasPermission(USER_EDIT)`) |\n| `updateUserRights()` | `admin/api/user/update-rights` | `grantUserRight($req.userId, \u2026)` | **none** (only `userHasPermission(USER_EDIT)`) |\n\nA logged-in administrator holding the delegable `edit_user` right \u2014 but  **not** SuperAdmin \u2014 can therefore:\n\n1. Set their own (or anyone\u0027s) `is_superadmin` flag to `true` via `admin/api/user/edit` \u2192 **full privilege escalation to SuperAdmin**.\n2. Grant arbitrary rights to any account via `admin/api/user/update-rights`.\n\nThis is exactly the threat model the parent advisory (GHSA-xvp4) calls out: \"organizations with multiple admin users where not all should have SuperAdmin access.\"\n\n## Anchors (upstream tag 4.1.3)\n\n- `phpmyfaq/src/phpMyFAQ/Controller/Administration/Api/UserController.php`\n  - `editUser()` lines 419-476; user-controlled `userId` at :433, user-controlled `is_superadmin` at :443, sink \n`$user \u003esetSuperAdmin((bool)$isSuperAdmin)` at **:463**. Only gate: `userHasPermission(PermissionType::USER_EDIT)` at :422.\n  - `updateUserRights()` lines 482-520; `userId` at :496, sink `grantUserRight($userId, \u2026)` at **:511**. Only gate at :485.\n  - `overwritePassword()` lines 419\u2026 \u2192 228-288; the **patched** guards at: 254-260 and: 269-273.\n- `phpmyfaq/src/phpMyFAQ/Controller/AbstractController.php` \u2014`userHasPermission()` :221-227 (checks one right only; non SuperAdmins can hold it).\n- `phpmyfaq/src/phpMyFAQ/User.php` \u2014 `setSuperAdmin()` :950-962 (`UPDATE faquser SET is_superadmin=\u2026 WHERE user_id=\u2026`, no guard); `isSuperAdmin()` :942-945.\n- `phpmyfaq/src/phpMyFAQ/Permission/BasicPermission.php` \u2014 `hasPermission()` :95-112 (SuperAdmin short-circuits true, else  `checkUserRight`).\n\nEvidence snapshots in this folder:\n`advisory/fix-diff-4.1.2-to-4.1.3.txt` (proves the fix touched only `overwritePassword`/`deleteUser`) and `advisory/vulnerable-siblings-4.1.3.txt` (the two unguarded methods as shipped). `git diff 4.1.2 4.1.3` shows **no change** to `editUser`, `updateUserRights`, `setSuperAdmin`, or `grantUserRight`.\n\n## Proof of Concept\n\n`poc/poc.php` (run log: `poc/run-log.txt`). Dependency-free: it builds phpMyFAQ\u0027s **real schema** (copied verbatim from\n`src/phpMyFAQ/Instance/Database/Sqlite3.php`) and executes the **verbatim SQL** that the shipped 4.1.3 methods run \u2014`setSuperAdmin` (UPDATE), `grantUserRight` (INSERT), and the real `hasPermission` / `checkUserRight` / `getRightId` queries \u2014 to prove the primitive:\n\n- Seeds a SuperAdmin (`admin`, id=1) and a non-SuperAdmin admin (`editor`, id=2) granted only `add_user`/`edit_user`/`delete_user`.\n- **Control:** the patched `overwritePassword` guard blocks `editor` changing the SuperAdmin (id=1) \u2014 confirms the fix works *there*.\n- **Exploit 1:** `editor` (non-SuperAdmin, passes `userHasPermission(edit_user)`) flips their own `is_superadmin` 0\u21921 \u2192 SuperAdmin. `VULNERABLE`.\n- **Exploit 2:** `editor` grants the `editconfig` right via `updateUserRights`. `VULNERABLE`.\n\nRun:\n```sh\nphp poc/poc.php   # -\u003e RESULT: VULNERABLE ... EXIT 0\n```\n\n### PoC scope (honest)\n\nThe PoC exercises the **privilege-escalation primitive** (the unguarded sinks + the real authorization-resolution logic) against the real schema. The full HTTP exploit additionally requires an authenticated admin session and a CSRF token (`editUser` verifies `update-user-data`, `updateUserRights` verifies `update-user-rights`); both are available to the authenticated admin attacker \u2014 the parent advisory\u0027s own PoC shows reading the CSRF token from admin pages. The controller-level **absence of an authorization guard** is established by source citation (the only gate is `userHasPermission(USER_EDIT)`), corroborated by the fix diff showing these methods were not modified.\n\n## Recommended fix\n\nApply the `overwritePassword` invariant to the siblings:\n- `editUser()`: reject `is_superadmin`/status/2FA changes unless `$this-\u003ecurrentUser-\u003eisSuperAdmin()`; never allow a non-SuperAdmin to edit a SuperAdmin or `protected` target. Treat `is_superadmin` as a SuperAdmin-only field (defeat the mass-assignment at :443/:463).\n- `updateUserRights()`: require `isSuperAdmin()` (or a privilege-level comparison) before `grantUserRight`; forbid granting rights the actor does not itself hold, and forbid targeting SuperAdmin/protected users.\n- `activate()` (`admin/api/user/activate`, :194-221) is a lower-impact sibling with the same shape \u2014 apply the same guard.",
  "id": "GHSA-985r-q3qp-299h",
  "modified": "2026-06-26T21:23:37Z",
  "published": "2026-06-26T21:23:37Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/thorsten/phpMyFAQ/security/advisories/GHSA-985r-q3qp-299h"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/thorsten/phpMyFAQ"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "phpMyFAQ has an incomplete fix for GHSA-xvp4-phqj-cjr3 \u2014 editUser() and updateUserRights() lack authorization guards"
}