CVE-2026-45134

Home/CVE/LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. Prior to LangSmith SDK Python 0.8.0 and

CVE

LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. Prior to LangSmith SDK Python 0.8.0 and

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.

HIGH · CVSS 7.1 EPSS 0.00036

Schedule remediation

CVSS base score ≥ 7.0

Sigma rules0 YARA rules0

Look this up elsewhere - one-click external pivots

NVD CVE.org CISA Vulners Exploit-DB GitHub PoC VulnCheck KEV GreyNoise

▸ How to read a CVE - triage first, then detect and patch

This page is every public fact about CVE-2026-45134, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.

Triage: should I act now? Four signals, and they are not interchangeable:

CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.

How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.

Then what - two workflows:

Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.

Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).

View attack path from CVE-2026-45134

◆

ATT&CK techniques

Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.

T1203 · Exploitation for Client Execution T1566 · Phishing

▤ Build a SIEM detection for these techniques

▤

CAPEC attack patterns

Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.

CAPEC-CAPEC-586 · Object Injection

⬡

Weakness Classification

CWE-502Deserialization of Untrusted Data

▤

Affected Packages

Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.

PyPI langchain HIGH fixed in 0.3.30

PyPI langchain-classic HIGH fixed in 1.0.7

PyPI langsmith HIGH fixed in 0.8.0

npm langsmith HIGH fixed in 0.6.0

▣

Scoring & Timeline

7.1

HIGH · CVSS v3.1 · [email protected]

View on NVD

Attack Vector

Network Adjacent Local Physical

Attack Complexity

Low High

Privileges Required

None Low High

User Interaction

None Required

Scope

Unchanged Changed

Confidentiality

None Low High

Integrity

None Low High

Availability

None Low High

Published to NVD27 May 2026 · 08:16 PM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N

SSVC triage · cisa-vulnrichment

Exploitation

none

Automatable

Technical impact

partial

SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.

🔗

References & Sources

Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.

https://github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-3644-q5cj-c5c7