CVE-2026-45134CWE-502

LangSmith Client SDK: Public prompt pull deserializes untrusted manifests without trust boundary warning

High · published May 27, 2026

CVSS v3.1
7.1
EPSS
0%
Percentile
26.7
In the wild
Unconfirmed
What it is

LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. Prior to LangSmith SDK Python 0.8.0 and JS/TS 0.6.0, the LangSmith SDK's prompt pull methods (pull_prompt / pull_prompt_commit in Python, pullPrompt / pullPromptCommit in JS/TS) fetch and deserialize prompt manifests from the LangSmith Hub. These manifests may contain serialized LangChain objects and model configuration that affect runtime behavior. When pulling a public prompt by owner/name identifier, the manifest content is controlled by an external party, but prior versions of the SDK did not distinguish this from pulling a prompt within the caller's own organization. This vulnerability is fixed in LangSmith SDK Python 0.8.0 and JS/TS 0.6.0.

The record
Technical detail
CVSS v3.1
7.1 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00344 · 26.7th percentile
Weakness
CWE-502 · Deserialization of Untrusted Data
Published
2026-05-27T19:35Z
EPSS history
Timeline
  • 27 MAY 19:35Z
    LangSmith Client SDK: Public prompt pull deserializes untrusted manifests without trust boundary warning
    cvelistv5