CVE Explorer

CVE-2026-40190

LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. Prior to 0.5.18, the LangSmith JavaScript/TypeScript SDK (langsmith) contains an incomplete prototype pollution fix in its internally vendored lodash set() utility. The baseAssignValue() function only guards against the __proto__ key, but fails to prevent traversal via constructor.prototype. This allows an attacker who controls keys in data processed by the createAnonymizer() API to pollute Object.prototype, affecti

Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:7c27d4e23909a9ea2bd7bab5730b8150ea42899ab1a4a76d77ea24cdfb2b7e2d

Known exploited

Not asserted

Disputed

Stale source

Conflicts

Affected products and versions

1 source assertion

{"product":"langsmith-sdk","vendor":"langchain-ai","versions":[{"status":"affected","version":"< 0.5.18"}]}

cve_program_cvelist_v5affected
urn:baitaphish:normalized-source-record:v2:c5ce5478439a15d1e0288ce20c5c3507afe9d511cb32fce038e038cb7a72ee98 · sha256:004841ab3c7b75e4… · /containers/cna/affected/0

Provider-owned CVSS observations

1 source assertion

{"metric":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":5.6,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L","version":"3.1"},"metric_type":"cvssV3_1"}

cve_program_cvelist_v5cvss
urn:baitaphish:normalized-source-record:v2:c5ce5478439a15d1e0288ce20c5c3507afe9d511cb32fce038e038cb7a72ee98 · sha256:004841ab3c7b75e4… · /containers/cna/metrics/0/cvssV3_1

CWE assertions

1 source assertion

{"cweId":"CWE-1321","description":"CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')","lang":"en","type":"CWE"}

cve_program_cvelist_v5cwe
urn:baitaphish:normalized-source-record:v2:c5ce5478439a15d1e0288ce20c5c3507afe9d511cb32fce038e038cb7a72ee98 · sha256:004841ab3c7b75e4… · /containers/cna/problemTypes/0/descriptions/0

Source references

1 source assertion

{"name":"https://github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-fw9q-39r9-c252","tags":["x_refsource_CONFIRM"],"url":"https://github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-fw9q-39r9-c252"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:c5ce5478439a15d1e0288ce20c5c3507afe9d511cb32fce038e038cb7a72ee98 · sha256:004841ab3c7b75e4… · /containers/cna/references/0

Attribution and limitations

CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

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