Medium severity · published Apr 23, 2026
CVE-2026-41182
LangSmith SDK: Streaming token events bypass output redaction
5.3
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 12% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LA
langsmith-sdk · langchain-ai
< 0.5.19; < 0.7.31 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-41182
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-41182
github.com
https://github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-rr7j-v2q5-chgv
More from langsmith-sdk
9.8
CVE-2026-40190
LangSmith Client SDKs has Prototype Pollution in langsmith-sdk via Incomplete `__proto__` Guard in Internal lodash `set()`
7.1
CVE-2026-45134
LangSmith Client SDK: Public prompt pull deserializes untrusted manifests without trust boundary warning
5.8
CVE-2026-25528
LangSmith Client SDK Affected by Server-Side Request Forgery via Tracing Header Injection
5.0
CVE-2026-59152
Arbitrary server-side file read in LangSmith SDK TracingMiddleware
