TI-2026-25346 Aliases CVE-2026-32887 GHSA-38f7-945m-qr2g

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

HIGH 66CWE-362Published 2026-03-20 · Updated 2026-03-25

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: High
Impact type: —
Confidentiality · integrity · availability: High · High · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00287 21st percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed effect (Effect-TS): 3.20.0effect (npm): 3.20.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Effect-TS	effect	before 3.20.0	3.20.0	Patch available	CNA
—	effect (npm)	before 3.20.0	3.20.0	Patch available	GHSA-38f7-945m-qr2g

effect VendorEffect-TS Affected before 3.20.0 Fixed in 3.20.0 Patch available CNA
effect (npm) Vendor— Affected before 3.20.0 Fixed in 3.20.0 Patch available GHSA-38f7-945m-qr2g

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:effectful:effect::::::node.js::*	before 3.20.0	Vulnerable	Effectful

cpe:2.3:a:effectful:effect:*:*:*:*:*:node.js:*:* Versions before 3.20.0 Vulnerable ·Effectful

Remediation

Fix · CNA effect (Effect-TS) Fixed in 3.20.0
Fix · GHSA-38f7-945m-qr2g effect (npm) Fixed in 3.20.0 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-32887
2026-10-03 Alias added: GHSA-38f7-945m-qr2g

References

TI-2026-84578 Effect: Cookie attribute injection via makeCookie() name, domain and path fields CVSS 4.0MEDIUM 6.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences