CVE-2026-49144
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedBrowserStack Runner through 0.9.5 contains a path traversal vulnerability in the _default HTTP handler in lib/server.js that allows unauthenticated network-adjacent attackers to read arbitrary files. Attackers can exploit the unauthenticated HTTP server bound on all interfaces to traverse outside the project root and access sensitive files.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceBrowserStack Runner versions up to 0.9.5 have a path traversal vulnerability in the _default HTTP handler in lib/server.js. An unauthenticated attacker can send specially crafted HTTP requests with directory traversal sequences (e.g., ../../) to read files outside the project root directory. The HTTP server binds to all network interfaces, making it accessible to network-adjacent attackers.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Adjacent
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify BrowserStack Runner versionRun 'npm list browserstack-runner' or check package.json for the installed version of browserstack-runnerAffected if Installed version is 0.9.5 or lower (any version through 0.9.5)
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Locate the vulnerable server fileFind lib/server.js in the BrowserStack Runner installation directory (typically node_modules/browserstack-runner/lib/server.js)Affected if The file exists and is present in the installation
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Check if HTTP server binds to network interfacesExamine the server startup configuration or code to determine if the HTTP handler binds to all interfaces (0.0.0.0) rather than localhost onlyAffected if Server binds to 0.0.0.0 or all network interfaces, making it externally accessible
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Inspect path validation in _default handlerOpen lib/server.js and locate the _default HTTP handler function. Search for path validation logic that checks for '..' sequences or resolves paths before serving filesAffected if No path validation code (no '..' check, no path.resolve comparison to root) exists in the _default handler
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Verify server is running and reachableConfirm the BrowserStack Runner HTTP server is actively running and accepting connectionsAffected if Server is running and accepts HTTP requests
You are affected if BrowserStack Runner version is 0.9.5 or lower, the HTTP server is bound to network interfaces, and the _default handler in lib/server.js lacks path traversal validation for '..' sequences.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataImplement strict path validation in the _default handler to ensure requested paths stay within the project root. Use path normalization and comparison to prevent traversal sequences. Consider binding the server to localhost only if external access is not required, and implement authentication.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-49144 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-49144 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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