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Fencer Vulns
high 7.5

CVE-2026-64641 json

Next.js: Denial of Service in App Router using Server Actions

published 2026-07-21 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-49381 , GHSA-m99w-x7hq-7vfj

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm next 15.5.21, 16.2.11
  • vercel next.js 15.5.21, 16.2.11

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-64641 updated cvss 7.5

next: Next.js: Denial of Service via crafted requests to App Router with Server Actions

  • Red Hat Build of Keycloak quarkus-websockets-next-spi 3.33.2.redhat-00004
    affected: no fix available
  • Red Hat Ceph Storage 5 rhceph/rhceph-5-dashboard-rhel8 Red Hat Ceph Storage 6 rhceph/rhceph-6-dashboard-rhel9 Red Hat Ceph Storage 7 rhceph/grafana-rhel9 Red Hat Ceph Storage 8 rhceph/grafana-rhel9 Red Hat Ceph Storage 9 rhceph/alloy-rhel10
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/disk-image-cuda-rhel9
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat JBoss Enterprise Application Platform 7 process-nextick-args 2.0.1 Red Hat Single Sign-On 7 process-nextick-args 2.0.1
    affected: no fix available “Fix deferred”
  • Red Hat Streams for Apache Kafka 3.2.1
    fixed: vendor fix RHSA-2026:54435
  • Red Hat Cryostat 4 i18next 25.10.10 Red Hat 3scale API Management Platform 2 3scale-amp2/system-rhel7, 3scale-amp2/backend-rhel8 Red Hat AMQ Broker 7 i18next 25.10.10 Red Hat build of Apache Camel - HawtIO 4 quarkus-websockets-next-spi 3.33.2.redhat-00004 Red Hat build of Apache Camel 4 for Quarkus 3 quarkus-websockets-next-spi 3.33.2.redhat-00004
    not affected: vulnerable code not present
  • Red Hat build of Apache Camel for Spring Boot 4 i18next 25.10.10
    not affected: component not present
  • Red Hat build of Apicurio Registry 3 quarkus-websockets-next-spi 3.33.2.redhat-00004 Red Hat build of Quarkus quarkus-websockets-next-deployment 3.27.4.redhat-00009 Red Hat Connectivity Link 1 rhcl-1/rhcl-console-plugin-rhel9 Red Hat Data Grid 8 i18next 25.10.10 Red Hat Enterprise Linux 7 firefox, firefox 140.12.0-1.el10_0
    not affected: vulnerable code not present
show 2 more
  • Red Hat Enterprise Linux 8 firefox, thunderbird, firefox 140.12.0-1.el10_0, thunderbird 140.12.0-1.el10_0 Red Hat Enterprise Linux 9 firefox, firefox-x11, thunderbird, firefox 140.12.0-1.el10_0, thunderbird 140.12.0-1.el10_0 Red Hat Enterprise Linux 10 firefox 140.12.0-1.el10_0, thunderbird 140.12.0-1.el10_0
    not affected: component not present
  • Red Hat JBoss Enterprise Application Platform 8 i18next 25.10.10 Red Hat Openshift Data Foundation 4 odf4/mcg-core-rhel9 Red Hat Trusted Artifact Signer rhtas/rekor-search-ui-rhel9 Red Hat streams for Apache Kafka 2 next 15.5.18
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.86% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
npm next
>=13.0.0, <15.5.21
>=16.0.0, <16.2.11
15.5.21
16.2.11

Affected products

  • vercel next.js

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of vercel/next.js published their own advisory on GitHub. Reviewed sources take precedence over it.