CVE-2026-32887

HIGH

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

Title source: cna
STIX 2.1

Description

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