CVE-2026-44576

MEDIUM LAB

Next.js: Cache poisoning in React Server Component responses

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2026-44576. PoCs published by dwisiswant0, XZ1r0.

AI-analyzed exploit summary This repository contains functional exploit proof-of-concept code for multiple CVEs affecting Next.js v16.2.4, including SSRF, XSS, DoS, and cache poisoning vulnerabilities. The PoCs are well-documented with detailed writeups, vulnerable code excerpts, and harnesses for testing.

Description

Next.js is a React framework for building full-stack web applications. From 14.2.0 to before 15.5.16 and 16.2.5, applications using React Server Components can be vulnerable to cache poisoning when shared caches do not correctly partition response variants. Under affected conditions, an attacker can cause an RSC response to be served from the original URL and poison shared cache entries so later visitors receive component payloads instead of the expected HTML. This vulnerability is fixed in 15.5.16 and 16.2.5.

Exploits (2)

github WORKING POC 127 stars
by dwisiswant0 · pythonpoc
https://github.com/dwisiswant0/next-16.2.4-pocs

This repository contains functional exploit proof-of-concept code for multiple CVEs affecting Next.js v16.2.4, including SSRF, XSS, DoS, and cache poisoning vulnerabilities. The PoCs are well-documented with detailed writeups, vulnerable code excerpts, and harnesses for testing.

Classification
Working Poc 95%
Attack Type
Ssrf | Xss | Dos | Auth Bypass | Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Next.js v16.2.4
No auth needed
Prerequisites: Vulnerable Next.js v16.2.4 installation · Network access to the target
devstral-2 · analyzed May 13, 2026 Full analysis →
github WORKING POC
by XZ1r0 · pythonpoc
https://github.com/XZ1r0/cve-2026-poc-collection/tree/main/other/next-16.2.4-pocs/poc/CVE-2026-44576_GHSA-wfc6-r584-vfw7

This repository contains a functional exploit for CVE-2026-44576, demonstrating an RSC HTML cache poisoning vulnerability in Next.js versions prior to 16.2.5. The exploit leverages a loose RSC header check and URL-suffix misclassification to poison shared CDN caches, serving RSC binary payloads as text/html.

Classification
Working Poc 100%
Attack Type
Other
Complexity
Moderate
Reliability
Reliable
Target: Next.js < 16.2.5
No auth needed
Prerequisites: Next.js deployment with cache components enabled · Dynamic route segment with query parameters
devstral-2 · analyzed May 21, 2026 Full analysis →

References (1)

Core 1
Core References

Scores

CVSS v3 5.4
EPSS 0.0002
EPSS Percentile 4.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:L

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-436
Status published
Products (5)
npm/next 14.2.0 - 15.5.16npm
npm/next 16.0.0 - 16.2.5npm
vercel/next.js 14.2.0 - 15.5.16
vercel/next.js >= 14.2.0, < 15.5.16
vercel/next.js >= 16.0.0, < 16.2.5
Published May 13, 2026
Tracked Since May 13, 2026