CVE-2026-41182 PUBLISHED

LangSmith SDK: Streaming token events bypass output redaction

Assigner: GitHub_M
Reserved: 17.04.2026 Published: 23.04.2026 Updated: 23.04.2026

LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. Prior to version 0.5.19 of the JavaScript SDK and version 0.7.31 of the Python SDK, the LangSmith SDK's output redaction controls (hideOutputs in JS, hide_outputs in Python) do not apply to streaming token events. When an LLM run produces streaming output, each chunk is recorded as a new_token event containing the raw token value. These events bypass the redaction pipeline entirely — prepareRunCreateOrUpdateInputs (JS) and _hide_run_outputs (Python) only process the inputs and outputs fields on a run, never the events array. As a result, applications relying on output redaction to prevent sensitive LLM output from being stored in LangSmith will still leak the full streamed content via run events. Version 0.5.19 of the JavaScript SDK and version 0.7.31 of the Python SDK fix the issue.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS Score: 5.3

Product Status

Vendor langchain-ai
Product langsmith-sdk
Versions
  • Version < 0.5.19 is affected
  • Version < 0.7.31 is affected

References

Problem Types

  • CWE-200: Exposure of Sensitive Information to an Unauthorized Actor CWE
  • CWE-359: Exposure of Private Personal Information to an Unauthorized Actor CWE
  • CWE-532: Insertion of Sensitive Information into Log File CWE