CVE-2022-21721

Name: CVE-2022-21721
Creator: NVD / NIST
Published: 2022-01-28T22:15:16.36+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.15%

Last modified Jun 17, 2026

CVE-2022-21721 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Next.js is a React framework. Starting with version 12.0.0 and prior to version 12.0.9, vulnerable code could allow a bad actor to trigger a denial of service attack for anyone using i18n functionality. EPSS estimates a 2.15% chance of exploitation in the next 30 days.

Description

Next.js is a React framework. Starting with version 12.0.0 and prior to version 12.0.9, vulnerable code could allow a bad actor to trigger a denial of service attack for anyone using i18n functionality. In order to be affected by this CVE, one must use next start or a custom server and the built-in i18n support. Deployments on Vercel, along with similar environments where invalid requests are filtered before reaching Next.js, are not affected. A patch has been released, `next@12.0.9`, that mitigates this issue. As a workaround, one may ensure `/${locale}/_next/` is blocked from reaching the Next.js instance until it becomes feasible to upgrade.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

2.15%

79.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Vercel	Next.Js	>= 12.0.0, < 12.0.9

References

https://github.com/vercel/next.js/pull/33503Patch, Third Party Advisory
https://github.com/vercel/next.js/releases/tag/v12.0.9Release Notes, Third Party Advisory
https://github.com/vercel/next.js/security/advisories/GHSA-wr66-vrwm-5g5xThird Party Advisory
https://github.com/vercel/next.js/pull/33503Patch, Third Party Advisory
https://github.com/vercel/next.js/releases/tag/v12.0.9Release Notes, Third Party Advisory
https://github.com/vercel/next.js/security/advisories/GHSA-wr66-vrwm-5g5xThird Party Advisory

Timeline

Published: Jan 28, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-21721?

How severe is CVE-2022-21721?

CVE-2022-21721 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.15% probability of exploitation in the next 30 days.

How do I fix CVE-2022-21721?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2022-21721?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST