Path Traversal in github.com/gtsteffaniak/filebrowser/backend (CVE-2026-54910)
Summary
Path traversal in github.com/gtsteffaniak/filebrowser/backend (CVE-2026-54910). Confidential information can be exposed externally. Exploitable via GET /api/media/subtitles. Mitigation: upgrade to 0.0.0-20260608182036-f3f4bbe80cb5 or later.
Original description
The description as published by the source.
Summary
The subtitlesHandler endpoint (GET /api/media/subtitles) accepts two user-controlled query parameters: path and name, both of which are used in filesystem operations without sanitization, creating two independent path traversal vectors.
The primary vector is the path parameter: it is passed directly to idx.GetRealPath() without calling SanitizeUserPath(), allowing an attacker to escape the storage root and set parentDir to any directory on the host. No existing anchor file is required.
The secondary vector is the name parameter: it is joined with parentDir via filepath.Join(parentDir, name) without stripping directory components, allowing traversal relative to any resolved parentDir.
Any authenticated user (regardless of role or permissions) can exploit either vector to read any text file readable by the server process, including /etc/passwd, SSH keys, database credentials, and JWT signing keys.
Details
1. path parameter lacks SanitizeUserPath() — primary vector (http/media.go:54)
userscope, err := d.user.GetScopeForSourceName(source)
// ...
realPath, _, err := idx.GetRealPath(userscope, path) // path is raw user input, no sanitization
// ...
parentDir := filepath.Dir(realPath) // line 59: attacker controls this directory
SanitizeUserPath() explicitly rejects .. segments:
func SanitizeUserPath(userPath string) (string, error) {
// ...
for _, segment := range segments {
if segme…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-54910 has been found in github.com/gtsteffaniak/filebrowser/backend.
Attackers can target a specific entry point like GET /api/media/subtitles over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.7/10.
What to do: upgrade github.com/gtsteffaniak/filebrowser/backend to 0.0.0-20260608182036-f3f4bbe80cb5 or later.
If unsure, ask your IT team or search "github.com/gtsteffaniak/filebrowser/backend CVE-2026-54910" on the vendor's site.
CVE-2026-54910 (github.com/gtsteffaniak/filebrowser/backend) — CWE-22 / CVSS v3 7.7
Attack vector: remote (network-reachable) / no user interaction
Attack surface: GET /api/media/subtitles / GET /media/subtitles / subtitlesHandler / path
Patched: 0.0.0-20260608182036-f3f4bbe80cb5 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Path traversal (CWE-22) exists in github.com/gtsteffaniak/filebrowser/backend. Attackers reach the vulnerable code path via GET /api/media/subtitles.
Check the vendor advisory for the affected versions of github.com/gtsteffaniak/filebrowser/backend. Attack surface: GET /api/media/subtitles / GET /media/subtitles / subtitlesHandler / path.
Severity: High (CVSS 7.7/10). Confidential information can be exposed externally.
Update to 0.0.0-20260608182036-f3f4bbe80cb5.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual GET /api/media/subtitles requests with malformed payloads or SQL meta-characters. Run grep -r 'github.com/gtsteffaniak/filebrowser/backend' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/gtsteffaniak/filebrowser/backend' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/gtsteffaniak/filebrowser/backendを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'GET /api/media/subtitles' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /api/media/subtitlesへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade github.com/gtsteffaniak/filebrowser/backend to 0.0.0-20260608182036-f3f4bbe80cb5ステージング環境で 0.0.0-20260608182036-f3f4bbe80cb5 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against GET /api/media/subtitles on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com