GHSA-9qr9-h5gf-34mp

Next.js is vulnerable to RCE in React flight protocol

Critical npm

Severity: 10.0 / 10; Critical · CVSS 3.1
Exploit chance (EPSS): 1.35%; Chance of exploitation in the next 30 days. Higher than 71.60% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-502 Deserialization of Untrusted Data
Fix: 15.0.5; Upgrade next to this version or later

Description

A vulnerability affects certain React packages<sup>1</sup> for versions 19.0.0, 19.1.0, 19.1.1, and 19.2.0 and frameworks that use the affected packages, including Next.js 15.x and 16.x using the App Router. The issue is tracked upstream as CVE-2025-55182.

Fixed in: React: 19.0.1, 19.1.2, 19.2.1 Next.js: 15.0.5, 15.1.9, 15.2.6, 15.3.6, 15.4.8, 15.5.7, 16.0.7, 15.6.0-canary.58, 16.1.0-canary.12+

The vulnerability also affects experimental canary releases starting with 14.3.0-canary.77. Users on any of the 14.3 canary builds should either downgrade to a 14.x stable release or 14.3.0-canary.76.

All users of stable 15.x or 16.x Next.js versions should upgrade to a patched, stable version immediately.

<sup>1</sup> The affected React packages are:

react-server-dom-parcel
react-server-dom-turbopack
react-server-dom-webpack

Affected versions

npm

Package	Vulnerable	Fixed in
next	`>= 14.3.0-canary.77, < 15.0.5`	`15.0.5`
next	`>= 15.1.0-canary.0, < 15.1.9`	`15.1.9`
next	`>= 15.2.0-canary.0, < 15.2.6`	`15.2.6`
next	`>= 15.3.0-canary.0, < 15.3.6`	`15.3.6`
next	`>= 15.4.0-canary.0, < 15.4.8`	`15.4.8`
next	`>= 15.5.0-canary.0, < 15.5.7`	`15.5.7`
next	`>= 16.0.0-canary.0, < 16.0.7`	`16.0.7`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

next npm → `15.0.5`

npm

npm install next@15.0.5

yarn

yarn add next@15.0.5

pnpm

pnpm add next@15.0.5

Severity breakdown

CVSS 3.1 10.0

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Changed
Confidentiality: High
Integrity: High
Availability: High

Weakness

CWE-502: Deserialization of Untrusted Data

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

How to prevent it

Architecture and Design, Implementation: If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
Implementation: When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
Implementation: Explicitly define a final object() to prevent deserialization.
Architecture and Design, Implementation: Make fields transient to protect them from deserialization. An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.
Implementation: Avoid having unnecessary types or gadgets (a sequence of instances and method invocations that can self-execute during the deserialization process, often found in libraries) available that can be leveraged for malicious ends. This limits the potential for unintended or unauthorized types and gadgets to be leveraged by the attacker. Add only acceptable classes to an allowlist. Note: new gadgets are constantly being discovered, so this alone is not a sufficient mitigation.
Architecture and Design, Implementation: Employ cryptography of the data or code for protection. However, it's important to note that it would still be client-side security. This is risky because if the client is compromised then the security implemented on the client (the cryptography) can be bypassed.
Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].

References

Advisories

nvd.nist.gov/vuln/detail/CVE-2025-55182

Packages

github.com/vercel/next.js

Timeline

Dec 3, 2025 Published
Sep 10, 2026 Last updated by the source

Advisory	Severity	Why it's related
CVE-2025-71389 Cal.com (calcom/cal.diy) before 5.9.9 is vulnerable to unauthenticated remote code execution because it bundles a version of Next.js whose React Server…	Critical	Linked by the source
GHSA-673q-mjm6-r5xr Next.js: Unauthenticated Remote Code Execution in `use cache` functions returning typed arrays	Critical	Also affects next
GHSA-2464-fhr4-w9xw Next.js: Unauthenticated Remote Code Execution in Image Optimization API when SVG files are used	Critical	Also affects next
GHSA-p3m5-59mp-jv5r Next.js: Denial of Service in App Router using Server Actions	High	Also affects next
GHSA-3w37-wq28-93x7 Next.js: Pending `use cache` fill can leak Draft Mode content into regular responses and persisted pages	Medium	Also affects next
GHSA-4jqv-mc3x-m676 Next.js has cache poisoning of SSG and ISR pages in self-hosted applications	Medium	Also affects next
GHSA-39w2-rjm5-chcv Next.js has information disclosure in development server's Model Context Protocol endpoint	Medium	Also affects next
GHSA-f87g-xv8r-7p7x Next.js has information disclosure in App Router metadata image routes via dynamicParams bypass	Medium	Also affects next

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