Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') Affecting librechat package, versions <0.8.4-r5
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-CHAINGUARDLATEST-LIBRECHAT-16113220
- published21 Apr 2026
- disclosed10 Apr 2026
Introduced: 10 Apr 2026
NewCVE-2026-40190 (opens in a new tab)How to fix?
Upgrade Chainguard librechat to version 0.8.4-r5 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream librechat package and not the librechat package as distributed by Chainguard.
See How to fix? for Chainguard relevant fixed versions and status.
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, affecting all objects in the Node.js process. This vulnerability is fixed in 0.5.18.