CVE-2026-25528: LangSmith Client SDK Affected by Server-Side Request Forgery via Tracing Header Injection

February 9, 2026

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.

References

github.com/advisories/GHSA-v34v-rq6j-cj6p
github.com/langchain-ai/langsmith-sdk
github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-v34v-rq6j-cj6p
nvd.nist.gov/vuln/detail/CVE-2026-25528

Code Behaviors & Features

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