CVE-2026-45134: langchain-ai langsmith-sdk · Deserialization of Untrusted Data
Affects langchain-ai langsmith-sdkSource CVE Database V5
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
- 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:NExploitation evidence
Disclosed: evidence found.
CVE published 27 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| langchain-ailangsmith-sdk | Affected
| Fixed in
|
| langchain-ailangsmith-sdk | Affected
| Fixed in
|
PyPIlangsmith-sdkpkg:pypi/langsmith-sdkOther threats | Affected
| Fixed in
|
npmlangsmith-sdkpkg:npm/langsmith-sdkOther threats | Affected
| Fixed in
|
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.