CVE-2026-64641: next.js — 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, crafted requests targeting Next.js applications using App Router with at least one Server Action can lead to excessive CPU usage blocking processing of further requests in the same process. This issue has been fixed in versions 15.5.21 and 16.2.11.

Is your site exposed to CVE-2026-64641?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.5

HIGH

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

EPSS — Exploit Prediction

0.0106

Probability of exploitation

0.62%

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-834 CWE-834

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/019628571641dec57aaf349ba0c360e3964e6f12 https://github.com/vercel/next.js/pull/96013 https://github.com/vercel/next.js/security/advisories/GHSA-m99w-x7hq-7vfj

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-2026-64641? +

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, crafted requests targeting Next.js applications using App Router with at least one Server Action can lead to excessive CPU usage blocking processing of further requests in the same process. This issue has been fixed in versions 15.5.21 and 16.2.11. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-64641? +

CVE-2026-64641 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0106, placing it in the 1th percentile for exploitation probability.

What products are affected by CVE-2026-64641? +

CVE-2026-64641 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-2026-64641? +

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.

Related Vulnerabilities

CVE-2026-53493

containerd is an open-source container runtime. Prior to versions 1.7.36, 2.0.13, 2.2.9, 2.3.6, and 2.4.1, a crafted OCI index graph …

CVE-2026-59644

In Bouncy Castle for Java before 1.85, MLS hash-ratchet honours arbitrary 32-bit generation counter from sender.

CVE-2026-115580

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.2, an attacker can craft a PDF with a …

CVE-2026-91137

Improper validation of specified quantity in input, Allocation of resources without limits or throttling, Excessive Iteration vulnerability in Apache Thrift …

CVE-2026-90798

A missing circuit-breaker in the replicator in Apache CouchDB 3.5.2 and below on all platforms allows the owner of a …

CVE-2026-87721

Uncontrolled Resource Consumption (CWE-400 / CWE-407) in the ANTLR 3 search query parser (QueryParser / Query.g) in Gerrit Code Review …