Vulnerability Database

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Total vulnerabilities in the database

LangSmith SDK TracingMiddleware: Arbitrary server-side file read — langsmith

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Summary

An attacker who can send an HTTP request to a server running the LangSmith SDK's TracingMiddleware can cause that server to read an arbitrary file from its local filesystem and upload the contents to LangSmith as a trace attachment. Depending on how the distributed trace system is deployed, triggering a read may not require authentication. Retrieving the contents requires read access to the LangSmith workspace the traces are sent to. The net effect is a trust-boundary crossing: a party with workspace trace-read access (for example a low-privilege workspace member, a contractor, or a compromised teammate account) gains the ability to read files from any server running TracingMiddleware, a capability outside that workspace's intended trust boundary.

Impact

Confidentiality (High): arbitrary read of files accessible to the server process, exposed to anyone with workspace trace-read access.

Details

Two defects combine. A field supplied through a tracing-propagation header was merged into the run without validation, allowing injection of run attributes including attachments (CWE-346). A type check intended to gate filesystem access did not match the type of the decoded input, so the guard never engaged (CWE-843). As a result, an attacker-named file is opened by the server and uploaded as a trace attachment by the background tracing thread (CWE-22).

Who can exploit this

  • Anyone reachable by HTTP can trigger the file read. Depending on how the distributed trace system is deployed, triggering may not require authentication.
  • Retrieving the file contents requires read access to the destination LangSmith workspace. The upload uses the server's own configured API key and workspace, which the attacker cannot redirect, so a zero-access outsider cannot retrieve the result; a workspace member, or anyone who has compromised one, can.

Remediation

Upgrade the Python SDK to >= 0.8.18.

Workarounds

Until upgrading, do not expose TracingMiddleware to untrusted HTTP traffic, and limit workspace trace-read access to trusted members.

Credits

First reported by @Ryu7zz.

  • Published: Jun 19, 2026
  • Updated: Jun 20, 2026
  • GHSA: GHSA-f4xh-w4cj-qxq8
  • Severity: High
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: High
  • Score: 7.7
  • AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

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Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

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