Path Traversal in browserstack-runner (CVE-2026-49144)
Summary
Path traversal in browserstack-runner (CVE-2026-49144). Confidential information can be exposed externally. Exploitable via _default.
Original description
The description as published by the source.
Summary
The HTTP server in browserstack-runner serves files from the project directory via the _default handler. This handler uses path.join(process.cwd(), uri) to resolve file paths but does not validate that the resulting path stays within the project root. Combined with the server binding on 0.0.0.0 (all interfaces) and the absence of any authentication, this allows an unauthenticated network-adjacent attacker to read arbitrary files from the host filesystem.
Root Cause
lib/server.js, lines 530–534 : _default handler:
'_default': function defaultHandler(uri, body, request, response) {
var filePath = path.join(process.cwd(), uri);
handleFile(filePath, request, response);
}
uri comes from url.parse(request.url).pathname (line 540), which preserves ../ sequences. path.join resolves them, producing absolute paths outside the project directory. No boundary check is performed before serving the file.
bin/cli.js, line 131 : server binding:
server.listen(parseInt(config.test_server_port, 10));
No hostname is specified, so Node.js binds on 0.0.0.0 (all interfaces).
No authentication: The _default handler does not call getWorkerUuid() or perform any authentication check.
Steps to Reproduce
Step 1 : Start the server (Terminal 1)
cd browserstack-runner
echo 'test' > _poc_test.html
echo '{"username":"X","key":"X","test_path":"_poc_test.html","test_framework":"qunit","browsers"…
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-2026-49144 has been found in browserstack-runner.
Attackers can target a specific entry point like _default over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 6.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "browserstack-runner CVE-2026-49144" on the vendor's site.
CVE-2026-49144 (browserstack-runner) — CWE-22 / CVSS v3 6.5
Attack vector: adjacent-network / unauthenticated / no user interaction
Attack surface: _default / uri / path.join / username
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 browserstack-runner. Attackers reach the vulnerable code path via _default without authentication.
Check the vendor advisory for the affected versions of browserstack-runner. Attack surface: _default / uri / path.join / username.
Severity: Medium (CVSS 6.5/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'browserstack-runner' . 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 'browserstack-runner' . | 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
browserstack-runnerを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in production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。本番ではアクセスログ・WAF 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 disclosure@vulncheck.com
- web github.com