Skip to content
Noroxi
NVD / CVE Program· CNA GitHub_M

CVE-2025-29927: Authorization Bypass in Next.js Middleware

CriticalCVSS 9.1 · v3.1—Weaponized Fix available

Noroxi assessment

Priority: This week (action score 66/100)

  • A ready-made attack module is public (Metasploit, Nuclei); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (Exploit-DB, GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 99.2% (FIRST EPSS); higher than 99.9% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: vercel next.js 12.3.5.

Don’t wait for the next maintenance window. Upgrade to vercel next.js 12.3.5 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Mar 21, 2025
Updated
Jun 17, 2026
EPSS
99.2% · 99th percentile

Report tools

JSON

Action score

66

This week

Don’t wait for the next maintenance window.

CVSS
36 / 40 · 9.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
30 / 30 · 99.2%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
9.1
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Weaponized exploit exists
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-29927

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Is the Next.js on your site affected?Scan JavaScript libraries

Your free account also gets you

  • CVE alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for vercel records

Is the Next.js on your site affected?Scan JavaScript libraries

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
vercelnext.js

Is the Next.js on your site affected?

The free JavaScript library scanner reads the Next.js version from the files your site loads, matches this record and other known vulnerabilities, and gives the safe version on the same branch. If the version can't be read, it says so. No account needed.

Scan JavaScript libraries

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • vercel next.js

    • >= 11.1.4, < 12.3.5, >= 14.0.0, < 14.2.25, >= 15.0.0, < 15.2.3, >= 13.0.0, < 13.5.9affected
Affected versions · NVD (4)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • vercel next.js11.1.4 and later · before 12.3.5
  • vercel next.js13.0.0 and later · before 13.5.9
  • vercel next.js14.0.0 and later · before 14.2.25
  • vercel next.js15.0.0 and later · before 15.2.3

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
npmnextfrom 12.0.0 · before 12.3.512.3.5
npmnextfrom 13.0.0 · before 13.5.913.5.9
npmnextfrom 14.0.0 · before 14.2.2514.2.25
npmnextfrom 15.0.0 · before 15.2.315.2.3

Same product

vercel: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-75604Next.js: Unauthenticated Remote Code Execution on windows-hosted servers
    60This week
  • CVE-2024-46982Cache Poisoning in next.js
    48Plan
  • CVE-2026-44578Next.js: Server-side request forgery in applications using WebSocket upgrades
    45Plan

Published before and after this one in the same product

  • ← EarlierCVE-2024-51479Dec 17, 2024 · Authorization bypass in Next.js
    31Monitor
  • ← EarlierCVE-2024-56332Jan 3, 2025 · Next.js Vulnerable to Denial of Service (DoS) with Server Actions
    21Monitor
  • Later →CVE-2025-30218Apr 2, 2025 · Next.js may leak x-middleware-subrequest-id to external hosts
    6Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
vercel next.js12.3.5 · descriptionVendor (CNA)
npm:next12.3.5Package registry (OSV)
npm:next13.5.9Package registry (OSV)
npm:next14.2.25Package registry (OSV)
npm:next15.2.3Package registry (OSV)

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Metasploit module ×1
  • Exploit-DB entry ×1
  • Nuclei detection template ×2
  • Proof-of-concept repository on GitHub ×50

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHub50 repositories2025-03-22 → 2025-03-30
Exploit-DB entrywebapps2025-04-05
Metasploit moduleauxiliary/scanner/http/nextjs_middleware_auth_bypassNext.js Middleware Authorization Bypass Scannerauxiliary2025-03-21
Nuclei detection templateNuclei template CVE-2025-29927-HEADLESS —
Nuclei detection templateNuclei template CVE-2025-29927 —

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Metasploitsame day
  2. Published
  3. First PoC+1 d
  4. TodayNov 14, 2026+603 d

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-64642493 days apartNext.js: Middleware / Proxy bypass in App Router applications using Turbopack and single locale
    33Monitor
  • CVE-2024-5147994 days apartAuthorization bypass in Next.js
    31Monitor

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Not on record for this CVE: EPSS history · researcher credit.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-285 · Improper Authorization

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records