CVE-2026-63188
Received Received - Intake

Path Traversal in Logto Tunnel

Publication date: 2026-08-19

Last updated on: 2026-08-19

Assigner: GitHub, Inc.

Description
Logto is the modern, open-source auth infrastructure for SaaS and AI apps. Prior to 0.3.9, the Logto Tunnel npm package enabled createStaticFileProxy from packages/tunnel/src/commands/tunnel/index.ts and passed request.url from static asset requests through packages/tunnel/src/commands/tunnel/utils.ts using path.join(staticPath, request.url) and then fs.open(requestPath, "r") without URL normalization or a containment check. When --experience-path was enabled and the tunnel port was reachable, an unauthenticated requester could send a path containing ../ to createStaticFileProxy and read files outside the configured static directory that were readable by the logto-tunnel process. The service used server.listen(port), which could expose the tunnel to other hosts depending on the platform and deployment. This issue is fixed in version 0.3.9.

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Meta Information

Published
2026-08-19
Last Modified
2026-08-19
Generated
2026-08-20
AI Q&A
2026-08-19
EPSS Evaluated
N/A
NVD
CVE-2026-63188
EUVD
EUVD-2026-62867

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
logto logto_tunnel 0.3.9
logto logto_tunnel to 0.3.9 (exc)
logto logto_tunnel to 0.3.8 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-22 The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Attack-Flow Graph

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Executive Summary

CVE-2026-63188 is a path traversal vulnerability in the Logto Tunnel npm package versions before 0.3.9. It allows unauthenticated attackers to read arbitrary files outside the configured static directory by sending crafted URLs with path traversal sequences like ../. The vulnerability occurs because the service does not validate or normalize file paths before serving static assets.

Detection Guidance

Check if you are running logto-tunnel version 0.3.8 or earlier. Inspect network traffic for requests containing path traversal sequences like ../ or encoded variants (..%2f, ..%5c). Use tools like curl to test for file access outside the static directory by sending crafted URLs to the tunnel port.

Impact Analysis

An attacker could exploit this to read sensitive files on the server, including configuration files, credentials, or other secrets readable by the Logto Tunnel process. This could lead to data breaches, unauthorized access to system files, or exposure of confidential information. The impact depends on what files are accessible and the permissions of the Logto Tunnel process.

Compliance Impact

This vulnerability could lead to non-compliance with GDPR, HIPAA, and other regulations by enabling unauthorized access to personal or sensitive data. If exploited, it may result in data breaches that violate privacy requirements, leading to legal penalties, reputational damage, and loss of trust. Organizations using affected versions must patch to avoid compliance violations.

Mitigation Strategies

Upgrade logto-tunnel to version 0.3.9 or later immediately. Ensure the tunnel service is not exposed to untrusted networks. Review file permissions to limit access to sensitive directories. Monitor logs for suspicious path traversal attempts.

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