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VulnerabilityPublished Updated

CVE-2026-45134: langchain-ai langsmith-sdk · Deserialization of Untrusted Data

Affects langchain-ai langsmith-sdkSource CVE Database V5

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Not known to be exploited · CVSS 7.1 High : upgrade to 0.8.0 or 0.6.0 soon.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.8.0, 0.6.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade langsmith-sdk to 0.8.0 or 0.6.0; langsmith-sdk to 0.8.0; langsmith-sdk to 0.6.0.

Affected software

ProductAffectedFixed in
langchain-ailangsmith-sdkAffected
  • <0.8.0
Fixed in
  • 0.8.0
langchain-ailangsmith-sdkAffected
  • <0.6.0
Fixed in
  • 0.6.0
PyPIlangsmith-sdkpkg:pypi/langsmith-sdkOther threatsAffected
  • <0.8.0
Fixed in
  • 0.8.0
npmlangsmith-sdkpkg:npm/langsmith-sdkOther threatsAffected
  • <0.6.0
Fixed in
  • 0.6.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade langsmith-sdk to Python version 0.8.0 or later, or JS/TS version 0.6.0 or later, where this vulnerability is fixed. Patch status is not explicitly confirmed beyond these version increments; check the vendor's official channels for any additional guidance.

Description

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.

References

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