CVE-2026-25528 Details
Description
LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. The LangSmith SDK's distributed tracing feature is vulnerable to Server-Side Request Forgery via malicious HTTP headers. An attacker can inject arbitrary api_url values through the baggage header, causing the SDK to exfiltrate sensitive trace data to attacker-controlled endpoints. When using distributed tracing, the SDK parses incoming HTTP headers via RunTree.from_headers() in Python or RunTree.fromHeaders() in Typescript. The baggage header can contain replica configurations including api_url and api_key fields. Prior to the fix, these attacker-controlled values were accepted without validation. When a traced operation completes, the SDK's post() and patch() methods send run data to all configured replica URLs, including any injected by an attacker. This vulnerability is fixed in version 0.6.3 of the Python SDK and 0.4.6 of the JavaScript SDK.
A Server-Side Request Forgery (SSRF) vulnerability has been identified in the LangSmith Client SDKs' distributed tracing feature. This issue allows attackers to inject arbitrary 'api_url' values through the 'baggage' header, leading the SDK to exfiltrate sensitive trace data to attacker-controlled endpoints. The vulnerability exists in the LangSmith SDKs for Python and JavaScript, affecting versions of the Python SDK prior to 0.6.3 and versions of the JavaScript SDK prior to 0.4.6. The issue arises because the SDK accepts unvalidated, attacker-controlled values in the 'baggage' header, which can include sensitive information such as LLM prompts, completions, and application metadata.
Users can update to version 0.6.3 of the Python SDK or version 0.4.6 of the JavaScript SDK. If an immediate upgrade is not possible, the 'baggage' header can be stripped or validated before being passed to the header parsing functions. Additionally, avoid using 'TracingMiddleware' with untrusted traffic.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Feb 9, 2026CISA-ADP
Assessed Feb 10, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-v34v-rq6j-cj6p | [email protected] | AdvisoryRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-918 | Server-Side Request Forgery (SSRF) | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| LangSmith | All versions |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Feb 9, 2026 | New CVE Received | [email protected] |