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Fencer Vulns
critical 9.1

CVE-2025-29927 in the critical feed json

Authorization Bypass in Next.js Middleware

published 2025-03-21 19 mo ago modified 2026-09-10 1 mo ago also EUVD-2025-7243 , GHSA-f82v-jwr5-mffw

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
99.2%
EPSS 99.2% chance of exploitation in 30 days, percentile 99.9%
public exploits
2
Metasploit, Exploit-DB, plus a Nuclei check

Summary

Next.js is a React framework for building full-stack web applications. Starting in version 1.11.4 and prior to versions 12.3.5, 13.5.9, 14.2.25, and 15.2.3, it is possible to bypass authorization checks within a Next.js application, if the authorization check occurs in middleware. If patching to a safe version is infeasible, it is recommend that you prevent external user requests which contain the x-middleware-subrequest header from reaching your Next.js application. This vulnerability is fixed in 12.3.5, 13.5.9, 14.2.25, and 15.2.3.

Patch / fix

  • npm next 12.3.5, 13.5.9, 14.2.25, 15.2.3
  • vercel next.js 12.3.5, 13.5.9, 14.2.25, 15.2.3

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-2025-29927 updated cvss 9.1

nextjs: Authorization Bypass in Next.js Middleware

  • Red Hat Enterprise Linux 7 firefox Red Hat Enterprise Linux 8 dotnet, firefox, dotnet8.0, dotnet9.0, dotnet/sdk, dotnet10.0, +45 more Red Hat Enterprise Linux 9 firefox, dotnet6.0, dotnet7.0, dotnet8.0, dotnet9.0, dotnet/sdk, +63 more Red Hat Enterprise Linux 10 firefox, dotnet8.0, dotnet9.0, dotnet10.0, thunderbird Red Hat Enterprise Linux AI (RHEL AI) rhelai1/ui-rhel9, rhelai1/pathservice-rhel9
    not affected: vulnerable code not present
  • Red Hat Trusted Artifact Signer rhtas/rekor-search-ui-rhel9
    not affected: vulnerable code not in execute path
  • Red Hat streams for Apache Kafka 2 com.github.streamshub-console
    not affected: inline mitigations already exist

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

Timeline

  1. First public exploit (Metasploit auxiliary/scanner/http/nextjs_middleware_auth_bypass)
  2. Published

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
19 mo ago

Exploit prediction

99.22% chance of exploitation in the next 30 days, higher than 99.9% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

CVSS scores

assigned by version score vector
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
GitHub 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm next
>=13.0.0, <13.5.9
>=14.0.0, <14.2.25
>=15.0.0, <15.2.3
>=12.0.0, <12.3.5
13.5.9
14.2.25
15.2.3
12.3.5

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.