CVE-2026-32887
HIGHEffect Bug: `AsyncLocalStorage` context lost/contaminated inside Effect fibers under concurrent load with RPC
Title source: cnaDescription
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.
Scores
CVSS v3
7.4
EPSS
0.0002
EPSS Percentile
3.8%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
no
Technical Impact
partial
Details
CWE
CWE-362
Status
published
Products (3)
Effect-TS/effect
< 3.20.0
effectful/effect
< 3.20.0
npm/effect
0 - 3.20.0npm
Published
Mar 20, 2026
Tracked Since
Mar 21, 2026