CVE-2026-32887
Effect Bug: `AsyncLocalStorage` context lost/contaminated inside Effect fibers under concurrent load with RPC
CVSS Score
7.4
EPSS Score
0.0%
EPSS Percentile
1th
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.
| CWE | CWE-362 |
| Vendor | effect-ts |
| Product | effect |
| Published | Mar 20, 2026 |
| Last Updated | Mar 25, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
Effect-TS / effect
< 3.20.0