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Fencer Intel
medium 6.5

CVE-2026-64649 json

Next.js: Server-Side Request Forgery in Server Actions on Custom Servers

published 3mo ago modified 16d ago also EUVD-2026-49571 , GHSA-89xv-2m56-2m9x

cvss
6.5
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 40%
public exploits
0
none known

Summary

Next.js is a React framework for building full-stack web applications. In versions 14.1.1 through 15.5.20 and 16.0.0 through 16.2.10, when a Server Action forwards or redirects a request, an attacker can cause the server to send that outbound request to a malicious host (Server-Side Request Forgery). This requires the attacker's request to control Host-associated headers. In some configurations, it's also possible to obtain internal values that weaken middleware/proxy authorization. Applications that use Server Actions are affected when the incoming host header is not fixed to a trusted value. This typically occurs on custom servers, or on deployments not behind a proxy that pins the host. Managed hosting pins the host upstream and is not affected; next start and standalone output do the same from version 14.2 onward. 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-2026-64649 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-2026-64649 updated cvss 8.2

next: Next.js: Server-Side Request Forgery via malicious host redirection 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_2 Red Hat Enterprise Linux 9 firefox, firefox-x11, thunderbird, firefox 140.12.0-1.el10_0, thunderbird 140.12.0-1.el10_2 Red Hat Enterprise Linux 10 firefox 140.12.0-1.el10_0, thunderbird 140.12.0-1.el10_2
    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

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 8.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 4.0 8.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/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 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm next
>=14.1.1, <15.5.21
>=16.0.0, <16.2.11
15.5.21
16.2.11

Affected products

  • vercel next.js

Classification

Weakness
  • CWE-918 Server-Side Request Forgery
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.