XSS in Vercel Next.js
CVE-2026-44580
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.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (15.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 15.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.000
Affected products
- Vercel Next.js — versions >= 13.0.0, < 15.5.16, >= 16.0.0, < 16.2.5
Weakness classification (CWE)
References
- github.com/vercel/next.js/security/advisories/GHSA-gx5p-jg67-6x7h (Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-44580?
- CVE-2026-44580 is a medium-severity vulnerability in Vercel Next.js, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-05-13.
- How severe is CVE-2026-44580?
- Medium severity. CVSS v3 base score is 6.1 out of 10.