CVE-2026-64646: next.js DoS — Fix

Description

Next.js is a React framework for building full-stack web applications. In versions 13.0.0 through 15.5.20 and 16.0.0 through 16.2.10, requests targeting Next.js applications using App Router with at least one Server Action can lead to excessive memory consumption if that Server Actions uses the Edge runtime. This issue has been fixed in versions 15.5.21 and 16.2.11.

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CVSS v3.1 Score

5.3

MEDIUM

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

EPSS — Exploit Prediction

0.0053

Probability of exploitation

0.42%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-770 CWE-770

Affected Products

Vendor	Product	Versions
vercel	next.js	13.0.0 — 15.5.21
vercel	next.js	16.0.0 — 16.2.11

References

Advisories & Patches

https://github.com/vercel/next.js/commit/57c31f724d746e86a9e8b92aa8be538a922446a4 https://github.com/vercel/next.js/commit/9a4651e754f70b12e397694ffc41f44c3ba8cc17 https://github.com/vercel/next.js/security/advisories/GHSA-4c39-4ccg-62r3

Other References

https://github.com/vercel/next.js/releases/tag/v15.5.21 https://github.com/vercel/next.js/releases/tag/v16.2.11

Frequently Asked Questions

What is CVE-2026-64646? +

Next.js is a React framework for building full-stack web applications. In versions 13.0.0 through 15.5.20 and 16.0.0 through 16.2.10, requests targeting Next.js applications using App Router with at least one Server Action can lead to excessive memory consumption if that Server Actions uses the Edge runtime. This issue has been fixed in versions 15.5.21 and 16.2.11. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-64646? +

CVE-2026-64646 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0053, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-64646? +

CVE-2026-64646 affects products from vercel, specifically: next.js. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-64646? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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