CVE-2026-32887 — Effect Bug: `AsyncLocalStorage` context lost/contaminated inside Effect fibers under concurrent load with RPC

CVE-2026-32887

Effect Bug: `AsyncLocalStorage` context lost/contaminated inside Effect fibers under concurrent load with RPC PUBLISHED

Description (CNA)

Effect is a TypeScript framework that consists of several packages that work together to help build TypeScript applications. Prior to version 3.20.0, when using `RpcServer.toWebHandler` (or `HttpApp.toWebHandlerRuntime`) inside a Next.js App Router route handler, any Node.js `AsyncLocalStorage`-dependent API called from within an Effect fiber can read another concurrent request's context — or no context at all. Under production traffic, `auth()` from `@clerk/nextjs/server` returns a different user's session. Version 3.20.0 contains a fix for the issue.

Affected (CNA)

Vendor / product	Versions
Effect-TS / effect	affected < 3.20.0

CWE

CWE-362

References

https://github.com/Effect-TS/effect/security/advisories/GHSA-38f7-945m-qr2g

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.