{"action":"Upgrade langsmith to 0.5.18 or later.","affected":[{"fixed":"0.5.18","introduced":"0"}],"component":"langsmith","cve_ids":["CVE-2026-40190"],"ecosystem":"npm","epss":0.00313,"exploited":false,"fixed_versions":["0.5.18"],"ghsa_id":"GHSA-fw9q-39r9-c252","id":"tcs_01M5KFPE77R1DS0N11RQFQ8TVF","modified_at":"2026-09-10T03:50:44.182038974Z","published_at":"2026-04-10T20:18:02Z","references":["https://osv.dev/vulnerability/GHSA-fw9q-39r9-c252","https://github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-fw9q-39r9-c252","https://nvd.nist.gov/vuln/detail/CVE-2026-40190","https://github.com/langchain-ai/langsmith-sdk/pull/2690","https://github.com/langchain-ai/langsmith-sdk/commit/31d3c3aec02892f4312baae112f817d6b2f0ebe3","https://github.com/langchain-ai/langsmith-sdk"],"severity":{"label":"medium","score":5.6},"sources":[{"source":"osv","source_id":"GHSA-fw9q-39r9-c252","url":"https://osv.dev/vulnerability/GHSA-fw9q-39r9-c252"}],"summary":"LangSmith Client SDKs has Prototype Pollution in langsmith-sdk via Incomplete `__proto__` Guard in Internal lodash `set()`"}