XSS in Vercel Next.js
CVE-2021-39178
Next.js is a React framework. Versions of Next.js between 10.0.0 and 11.0.0 contain a cross-site scripting vulnerability. In order for an instance to be affected by the vulnerability, the `next.config.js` file must have `images.domains` array assigned and the image host assigned in `images.domains` must allow user-provided SVG. If the `next.config.js` file has `images.loader` assigned to something other than default or the instance is deployed on Vercel, the instance is not affected by the vulnerability. The vulnerability is patched in Next.js version 11.1.1.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.011 (63.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.
Affected products
- Vercel Next.js — versions >= 10.0.0, < 11.1.1
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Patch, Third Party Advisory)
- security-advisories@github.com (Patch, Third Party Advisory, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2021-39178?
- CVE-2021-39178 is a high-severity vulnerability in Vercel Next.js, classified under Cross-site Scripting. CVSS score: 7.5/10. Published 2021-08-31.
- How severe is CVE-2021-39178?
- High severity. CVSS v3 base score is 7.5 out of 10.