PyPI: langchain
CVE-2026-45134
Safety vulnerability ID: SFTY-20260513-51019
Affected versions of the LangSmith SDK package are vulnerable to Deserialization of Untrusted Data due to improper handling of prompt manifests fetched from the LangSmith Hub. The `pull_prompt` and `pull_prompt_commit` methods in Python, as well as `pullPrompt` and `pullPromptCommit` in JS/TS, deserialize prompt manifests that may contain serialized LangChain objects and model configurations controlled by external parties. An attacker can exploit this by publishing a malicious prompt to the LangSmith Hub, which, when pulled by `owner/name`, can lead to Server-side Request Forgery (SSRF), prompt injection, or behaviour manipulation by altering application configurations with attacker-supplied arguments.
Overview
LangSmith SDK: Public prompt pull deserializes untrusted manifests without trust boundary warning
Advisory
langsmith – Deserialization of Untrusted Data
How to Fix
Mitigation and Workarounds
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Vulnerable Functions
Functions linked to known vulnerabilities.
References
- https://getsafety.com/vulnerabilities/SFTY-20260513-51019/CVE-2026-45134
- https://github.com/langchain-ai/langchain/commit/c4db9c0042a70fcb9a6ab1137d4f98925d326b2b
- https://github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-3644-q5cj-c5c7
- https://nvd.nist.gov/vuln/detail/CVE-2026-45134
- https://github.com/advisories/GHSA-3644-q5cj-c5c7
Verified by Safety
Our Cybersecurity Intelligence Team reviewed this vulnerability. We combine public data with our own research to find issues not yet reported to public sources.
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