CVE-2026-45134
HIGHCVE-2026-45134 is a high-severity (CVSS 7.1) remote code execution vulnerability in langsmith. O3 Security confirms whether CVE-2026-45134 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
LangSmith Client SDK: Public prompt pull deserializes untrusted manifests without trust boundary warning
Real-World Exposure
langsmith🐍langsmith🐍langchain-classic🐍langchainReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm, PyPI packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | langsmith | all versions | 0.6.0 |
| 🐍PyPI | langsmith | all versions | 0.8.0 |
| 🐍PyPI | langchain-classic | all versions | 1.0.7 |
| 🐍PyPI | langchain | all versions | 0.3.30 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for langsmith. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update langsmith to 0.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-45134 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-45134 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-45134. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-45134 in your dependencies?
O3 detects CVE-2026-45134 across npm, PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.