CVE-2026-41182 LangSmith SDK: Streaming token events bypass output redaction
The LangSmith SDK fails to redact sensitive data in streaming token events, allowing attackers or unauthorized users to view raw LLM outputs.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-41182?
CVE-2026-41182 is a medium-severity vulnerability in langchain-ai langsmith-sdk, published on 23 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-41182?
5 open source packages ship an affected version, including langsmith.
| Package | Affected | Fixed in |
|---|---|---|
langsmith PyPI | All versions | 0.7.31 |
langsmith PyPI | All versions | 0.7.31 |
langsmith PyPI | All versions | 0.7.31 |
langsmith npm | All versions | 0.5.19 |
langsmith npm | All versions | 0.5.19 |
How do I fix CVE-2026-41182?
Upgrade langsmith to a fixed version for your release line: 0.7.31 or 0.5.19.
Is CVE-2026-41182 being exploited?
There is no known exploitation of CVE-2026-41182 in the wild and no public exploit code.
Sources
Also known as ECHO-e53b-c949-a5db, GHSA-rr7j-v2q5-chgv, MINI-29wm-j3h3-g45r, MINI-3xr3-4qc3-f826, MINI-4cgg-hp2p-4q9j, MINI-5g2c-v2pv-g4cp and 12 more.