Next.js: Cross-site scripting in beforeInteractive scripts with untrusted input
Title source: cnaExploitation Summary
EIP tracks 2 public exploits for CVE-2026-44580. PoCs published by dwisiswant0, XZ1r0.
AI-analyzed exploit summary This repository contains functional proof-of-concept exploits for multiple CVEs in Next.js v16.2.4, including detailed write-ups, vulnerable code excerpts, and runnable exploit scripts. The PoCs cover vulnerabilities such as SSRF, XSS, DoS, and cache poisoning, with a focus on reverse-engineered security issues fixed in Next.js v16.2.5.
Description
Next.js is a React framework for building full-stack web applications. From 13.0.0 to before 15.5.16 and 16.2.5, applications that use beforeInteractive scripts together with untrusted content can be vulnerable to cross-site scripting. In affected versions, serialized script content was not escaped safely before being embedded into the document, which could allow attacker-controlled input to break out of the intended script context and execute arbitrary JavaScript in a visitor's browser. This vulnerability is fixed in 15.5.16 and 16.2.5.
Exploits (2)
This repository contains functional proof-of-concept exploits for multiple CVEs in Next.js v16.2.4, including detailed write-ups, vulnerable code excerpts, and runnable exploit scripts. The PoCs cover vulnerabilities such as SSRF, XSS, DoS, and cache poisoning, with a focus on reverse-engineered security issues fixed in Next.js v16.2.5.
This repository contains a functional exploit for CVE-2026-44580, a Next.js XSS vulnerability in the `next/script` component with `strategy='beforeInteractive'`. The exploit demonstrates how unescaped HTML characters in JSON-stringified props can break out of inline scripts, leading to arbitrary JavaScript execution.
References (1)
Scores
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N