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Medium 5.3Published Apr 22, 2026

CVE-2026-41182LangSmith SDK: Streaming token events bypass output redaction

Updated under an hour ago ()

Does this affect you?

It affects langchain-ai langsmith-sdk. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness (CWE)
CWE-200, CWE-359, CWE-532
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Awaiting Analysis
Record last updated
Apr 23, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
langchain-ai langsmith-sdk
langchain_ai:langsmith_sdk (from the name)
before 0.5.19; before 0.7.31
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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