Critical RCE Vulnerabilities in React and Next.js
1–10 of 92 posts
Re: Critical RCE Vulnerabilities in React and Next.js
#2Just to simplify this - our exploitation tests so far have shown that a standard Next.js application created via create-next-app and built for production is vulnerable to CVE-2025-66478 without any specific code modifications by the developer - so this is essentially exploitable out-of-the-box.
Re: Critical RCE Vulnerabilities in React and Next.js
#3Unsafe deserialization is a very 2010 Ruby on Rails sort of vulnerability. It is strangely interesting that such a vulnerability was introduced so late in the lifetime of these frameworks. It must be a very sneaky vulnerability given how cautious we have become around deserialization since then.
Re: Critical RCE Vulnerabilities in React and Next.js
#4Wow, I am at a loss for words how serious this is. Looking forward to a more technical write up.
This might cause quite a lot of chaos and leaked code / credentials over the next couple of weeks.
Re: Critical RCE Vulnerabilities in React and Next.js
#5These wiz.io blog posts should be banned from HN; AFAICT, they're AI generated. Here's the original post with the details: https://react.dev/blog/2025/12/03/critical-security-vulnerab... - the vulnerability was not found by a Wiz employee at all, and the Wiz article (unlike the react.dev article) does not provide any meaningful technical information.
The important part to know:
- Even if your app does not implement any React Server Function endpoints it may still be vulnerable if your app supports React Server Components.
- The vulnerability is present in versions 19.0, 19.1.0, 19.1.1, and 19.2.0 of: react-server-dom-webpack, react-server-dom-parcel, react-server-dom-turbopack
- Some React frameworks and bundlers depended on, had peer dependencies for, or included the vulnerable React packages. The following React frameworks & bundlers are affected: next, react-router, waku, @parcel/rsc, @vitejs/plugin-rsc, and rwsdk.
Re: Critical RCE Vulnerabilities in React and Next.js
#6Unsafe deserialization is a very 2010 Ruby on Rails sort of vulnerability. It is strangely interesting that such a vulnerability was introduced so late in the lifetime of these frameworks. It must be a very sneaky vulnerability given how cautious we have become around deserialization since then.
I'm willing to bet that this is linked to the magic __proto__ object namespace in JavaScript
Re: Critical RCE Vulnerabilities in React and Next.js
#7Unsafe deserialization is a very 2010 Ruby on Rails sort of vulnerability. It is strangely interesting that such a vulnerability was introduced so late in the lifetime of these frameworks. It must be a very sneaky vulnerability given how cautious we have become around deserialization since then.
The React Server Components wire format (Flight) is relatively novel and very new (it has existed in React stable for just a year). This is not a simple JSON parsing bug.
Re: Critical RCE Vulnerabilities in React and Next.js
#8Here's a patch diff:
https://github.com/vercel/next.js/compare/v15.0.4...v15.0.5
It looks like the fix is checking hasOwnProperty, so it's almost certainly an issue with prototype chain pollution.
Re: Critical RCE Vulnerabilities in React and Next.js
#9These wiz.io blog posts should be banned from HN; AFAICT, they're AI generated. Here's the original post with the details: https://react.dev/blog/2025/12/03/critical-security-vulnerab... - the vulnerability was not found by a Wiz employee at all, and the Wiz article (unlike the react.dev article) does not provide any meaningful technical information. The important part to know: - Even if your app does not implement a…
>AFAICT, they're AI generated.
What is the "tell"? I'm not saying they are or aren't, but... people say this about literally everything now and it's typically some flimsy reasoning like "they used a bullet point". I don't see anything in particular that makes me think ai over a standard template some junior fills out.
>the vulnerability was not found by a Wiz employee at all
I've re-read the Wiz article a few times. Maybe I'm just dumb, but where did Wiz claim to have found this vulnerability?
Re: Critical RCE Vulnerabilities in React and Next.js
#10These wiz.io blog posts should be banned from HN; AFAICT, they're AI generated. Here's the original post with the details: https://react.dev/blog/2025/12/03/critical-security-vulnerab... - the vulnerability was not found by a Wiz employee at all, and the Wiz article (unlike the react.dev article) does not provide any meaningful technical information. The important part to know: - Even if your app does not implement a…
Hey mmsc, first of all - the blogs are not AI Generated!
Second of all, the blog did add more information
"In our experimentation, exploitation of this vulnerability had high fidelity, with a near 100% success rate and can be leveraged to a full remote code execution. The attack vector is unauthenticated and remote, requiring only a specially crafted HTTP request to the target server. It affects the default configuration of popular frameworks. "
In the end - if it helped spreading the news about this risk so teams can fix them faster, then this is our end-goal with these blog posts : )