CVE-2026-45134: LangSmith SDK insecure prompt manifest deserialization

# CVE-2026-45134: LangSmith SDK insecure prompt manifest deserialization

https://gcdradar.vercel.app/incidents/cve-2026-45134-langsmith-sdk-insecure-prompt-manifest-deseri · AIR-2026-0655 · closed 2026-05-13

- Lane: Patch now
- Severity: 2 (Disclosed vulnerability)
- Fix status: Fix status unknown
- First reported: 2026-05-13
- AI role: Attack on AI
- Products: LangSmith SDK
- CVE ids: CVE-2026-45134
- CVSS: 7.1

## Summary

The LangSmith SDK fetches and deserializes external prompt manifests from the LangSmith Hub without trust boundary validation. This flaw allows malicious manifests to affect runtime behavior and execute untrusted objects.

## What to do

No action recorded; read the sources below and the vendor's advisory.

## Latest updates

- 2026-05-27: CVE-2026-45134: LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. (https://nvd.nist.gov/vuln/detail/CVE-2026-45134)
- 2026-05-13: CVE-2026-45134: LangSmith SDK: Public prompt pull deserializes untrusted manifests without trust boundary warning (https://github.com/advisories/GHSA-3644-q5cj-c5c7)

## Sources

- 2026-05-13 GitHub Advisory Database: CVE-2026-45134: LangSmith SDK: Public prompt pull deserializes untrusted manifests without trust boundary warning https://github.com/advisories/GHSA-3644-q5cj-c5c7
- 2026-05-27 NVD: CVE-2026-45134: LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. https://nvd.nist.gov/vuln/detail/CVE-2026-45134

Verify against the vendor's advisory before changing production. Data CC BY-SA 4.0, https://gcdradar.vercel.app.