TI-2026-22319 Aliases CVE-2026-27977 GHSA-jcc7-9wpm-mj36

Next.js: null origin can bypass dev HMR websocket CSRF checks

LOW 11CWE-1385Published 2026-03-17 · Updated 2026-03-18

Key facts

Attack vector: Network
Privileges required: None
User interaction: Passive
Attack complexity: Low
Attack requirements: Present
Impact type: —
Confidentiality · integrity · availability: Low · Low · None
Fix status: Partial Red Hat: 5 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat.

Summary

Next.js is a React framework for building full-stack web applications. Starting in version 16.0.1 and prior to version 16.1.7, in `next dev`, cross-site protection for internal websocket endpoints could treat `Origin: null` as a bypass case even if `allowedDevOrigins` is configured, allowing privacy-sensitive/opaque contexts (for example sandboxed documents) to connect unexpectedly. If a dev server is reachable from attacker-controlled content, an attacker may be able to connect to the HMR websocket channel and interact with dev websocket traffic. This affects development mode only. Apps without a configured `allowedDevOrigins` still allow connections from any origin. The issue is fixed in version 16.1.7 by validating `Origin: null` through the same cross-site origin-allowance checks used for other origins. If upgrading is not immediately possible, do not expose `next dev` to untrusted networks and/or block websocket upgrades to `/_next/webpack-hmr` when `Origin` is `null` at the proxy.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00182 7th percentileScored 2026-11-07

Fix Partial next.js (vercel): 16.1.7next (npm): 16.1.7Red Hat: 5 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
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
vercel	next.js	16.0.1 to before 16.1.7	16.1.7	Patch available	CNA
—	next (npm)	16.0.1 to before 16.1.7	16.1.7	Patch available	GHSA-jcc7-9wpm-mj36

next.js Vendorvercel Affected 16.0.1 to before 16.1.7 Fixed in 16.1.7 Patch available CNA
next (npm) Vendor— Affected 16.0.1 to before 16.1.7 Fixed in 16.1.7 Patch available GHSA-jcc7-9wpm-mj36

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:vercel:next.js::::::node.js::*	16.0.1 to before 16.1.7	Vulnerable	vercel

cpe:2.3:a:vercel:next.js:*:*:*:*:*:node.js:*:* Versions 16.0.1 to before 16.1.7 Vulnerable ·vercel

Remediation

Fix · CNA next.js (vercel) Fixed in 16.1.7
Fix · GHSA-jcc7-9wpm-mj36 next (npm) Fixed in 16.1.7 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux 9	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux AI (RHEL AI) 3	Affected	No fix yet: Fix deferred
Red Hat Trusted Artifact Signer	Affected	No fix yet: Fix deferred
streams for Apache Kafka 2	Affected	No fix yet: Fix deferred
streams for Apache Kafka 3	Affected	No fix yet: Fix deferred

Timeline

2026-10-02 Threatist record created from CVE-2026-27977
2026-10-03 Alias added: GHSA-jcc7-9wpm-mj36

References

Patch 1

https://github.com/vercel/next.js/commit/862f9b9bb41d235e0d8cf44aa811e7fd118cee2a

Advisory 2

Other 2

TI-2025-34861 Deserialization of untrusted data in Meta react-server-dom-webpack KEVCVSS 3.1CRITICAL 10.0
TI-2025-21309 Authorization Bypass in Next.js Middleware CVSS 3.1CRITICAL 9.1
TI-2025-34863 Deserialization of untrusted data in Meta react-server-dom-webpack CVSS 3.1HIGH 7.5
TI-2024-31371 Cache Poisoning in next.js CVSS 3.1HIGH 7.5
TI-2023-24914 Next.js before 13.4.20-canary.13 lacks a cache-control header and thus empty prefetch… CVSS 3.1HIGH 7.5
TI-2026-32490 Next.js: Server-side request forgery in applications using WebSocket upgrades CVSS 3.1HIGH 8.6

See all 62 →

Sources

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