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CVE-2026-25528

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

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 5.8 · Medium · EPSS 0.3% · Fix available

Published
Updated

Stack: python · node

Affected products and versions

  • langsmith-sdk

    Versions
    • >= 0.4.10, <0.6.3: Affected

    No fix published

  • langsmith PyPI

    Versions
    • 0.4.10
    • 0.4.11
    • 0.4.12
    • 0.4.13
    • 0.4.14
    • 0.4.15
    • 0.4.16
    • 0.4.17
    • 0.4.18
    • 0.4.19
    • 0.4.20
    • 0.4.21
    • 0.4.22
    • 0.4.23
    • 0.4.24
    • 0.4.25
    • 0.4.26
    • 0.4.27
    • 0.4.28
    • 0.4.29
    • 0.4.30
    • 0.4.31
    • 0.4.32
    • 0.4.32rc0
    • 0.4.33
    • 0.4.34
    • 0.4.35
    • 0.4.35rc1
    • 0.4.36
    • 0.4.37
    • 0.4.38
    • 0.4.39
    • 0.4.39rc0
    • 0.4.39rc1
    • 0.4.40
    • 0.4.41
    • 0.4.42
    • 0.4.42rc0
    • 0.4.43
    • 0.4.43rc0
    • 0.4.44
    • 0.4.45
    • 0.4.46
    • 0.4.47
    • 0.4.48
    • 0.4.49
    • 0.4.50
    • 0.4.51
    • 0.4.52
    • 0.4.53
    • 0.4.54
    • 0.4.54rc0
    • 0.4.55
    • 0.4.56
    • 0.4.57
    • 0.4.58
    • 0.4.59
    • 0.4.60
    • 0.5.0
    • 0.5.1
    • 0.5.2
    • 0.6.0
    • 0.6.0rc0
    • 0.6.1
    • 0.6.2
    Affected ranges
    • ECOSYSTEM: ≥ 0.4.10, < 0.6.3

    Update to 0.6.3

  • langsmith npm

    Affected ranges
    • SEMVER: ≥ 0.3.41, < 0.4.6

    Update to 0.4.6

Original sources

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