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Fencer Intel
medium 5.3

CVE-2026-64646 json

Next.js: Unbounded Server Action payload in Edge runtime

published 3mo ago modified 16d ago also EUVD-2026-49401 , GHSA-4c39-4ccg-62r3

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
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, 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.

Patch / fix

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

Is CVE-2026-64646 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2026-64646 updated cvss 7.5

next: Next.js: Denial of Service via excessive memory consumption in Server Actions

  • 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 Streams for Apache Kafka 3.2.1
    fixed: vendor fix RHSA-2026:54435
  • Red Hat Enterprise Linux 7 firefox, firefox 140.12.0-1.el10_0
    not affected: vulnerable code not present
  • 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 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
no
Technical impact
partial
Assessed
3mo ago

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/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 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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
  • CWE-770 Allocation of Resources Without Limits or Throttling
Technology feeds

References

Sources

Fencer Intel 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.