CVE-2026-41182: LangSmith SDK Streaming Token Events Bypass Output Vulnerability

MODERATE
Advisory Identifier: GHSA-rr7j-v2q5-chgv
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CVSS 5.3
CWE-532 CWE-200 CWE-359
Published
Advisory Summary

CVE-2026-41182 is a MODERATE (CVSS 5.3) streaming token events bypass output vulnerability (CWE-532: Insertion of Sensitive Information into Log File) affecting LangSmith SDK libraries in the npm ecosystem. The issue involves streaming token events bypass output redaction. Remediation is available by upgrading affected packages to version 0.5.19, 0.7.31.

CVE-2026-41182 at a Glance

CVE Identifier CVE-2026-41182
GHSA Identifier GHSA-rr7j-v2q5-chgv
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-532: Insertion of Sensitive Information into Log File
Affected Product LangSmith SDK
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2026-41182

To remediate this vulnerability, upgrade all affected LangSmith SDK dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

langsmith fixed: 0.5.19 
npm install langsmith@0.5.19
langsmith fixed: 0.7.31 
pip install langsmith>=0.7.31
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls langsmith

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-41182, inspect your project dependencies using npm:

npm ls langsmith

Analyze the terminal output to locate any version of LangSmith SDK in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.5.19), your application is affected.

Note: The npm ls langsmith command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-532: Insertion of Sensitive Information into Log File, where the product writes sensitive information to a log file. In LangSmith SDK, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Summary 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. ## Details **Both JS and Python SDKs are affected.** The same pattern exists in both: - **JS SDK**: `traceable.ts:997-1003` and `traceable.ts:1044-1050` - **Python SDK**: `run_helpers.py:1924` and `run_helpers.py:1996` In both SDKs, `new_token` events with raw `kwargs.token` values are added during streaming, and the redaction pipeline (`hideOutputs` in JS, `hide_outputs` in Python) only processes `inputs`/`outputs` — never `events`.

CVE-2026-41182 Affected LangSmith SDK Versions

2 component(s)
Fixed Versions:
0.5.190.7.31
Product / Package Ecosystem Affected Versions Fixed Version
langsmith
npm/langsmith
npm
< 0.5.19
0.5.19
langsmith
pypi/langsmith
PyPI
< 0.7.31
0.7.31

References

GitHub Advisory / Wiki ADVISORY
https://github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-rr7j-v2q5-chgv
NVD — CVE-2026-41182 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-41182
LangSmith SDK Source Repository REPOSITORY
https://github.com/langchain-ai/langsmith-sdk

Frequently Asked Questions

What is CVE-2026-41182?
CVE-2026-41182 is a security vulnerability in LangSmith SDK involving Streaming token events bypass output redaction under CWE-532: Insertion of Sensitive Information into Log File.
Which LangSmith SDK versions are affected?
Affected versions include releases prior to 0.5.19, 0.7.31 across affected packages: langsmith.
What version fixes CVE-2026-41182?
Upgrading to 0.5.19, 0.7.31 (or the latest patched release for your respective branch) resolves the vulnerability.
Is langsmith affected?
Yes, langsmith is affected in releases prior to 0.5.19, 0.7.31. Upgrade your dependency to 0.5.19, 0.7.31 or later.
What is the CVSS score of CVE-2026-41182?
CVE-2026-41182 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.
What CWE is associated with CVE-2026-41182?
CVE-2026-41182 is classified under CWE-532: Insertion of Sensitive Information into Log File (The product writes sensitive information to a log file.).
How can I check npm dependencies for CVE-2026-41182?
Run the dependency tree command: 'npm ls langsmith'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
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  "schema_version" : "1.4.0",
  "id" : "GHSA-rr7j-v2q5-chgv",
  "modified" : "2026-04-24T20:52:13Z",
  "published" : "2026-04-16T01:20:37Z",
  "aliases" : [ "CVE-2026-41182" ],
  "summary" : "LangSmith SDK: Streaming token events bypass output redaction",
  "details" : "## Summary\n\nThe 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.\n\n## Details\n\n**Both JS and Python SDKs are affected.** The same pattern exists in both:\n\n- **JS SDK**: `traceable.ts:997-1003` and `traceable.ts:1044-1050`\n- **Python SDK**: `run_helpers.py:1924` and `run_helpers.py:1996`\n\nIn both SDKs, `new_token` events with raw `kwargs.token` values are added during streaming, and the redaction pipeline (`hideOutputs` in JS, `hide_outputs` in Python) only processes `inputs`/`outputs` — never `events`.",
  "severity" : [ {
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  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200", "CWE-359", "CWE-532" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-16T01:20:37Z",
    "nvd_published_at" : "2026-04-23T02:16:16Z"
  }
}