CVE-2024-51479Network attack vector

Unauthenticated authorization bypass via unvalidated locale query

Published Dec 17, 2024 · Updated Dec 17, 2024

Improper authorization in Next.js 9.5.5 through 14.2.14 allows remote attackers to access protected root-level pages. The server accepts unvalidated __nextLocale query values and normalizes the request pathname differently from the path evaluated by authorization middleware. Exposure requires a self-hosted affected application that bases authorization on middleware pathname checks; Vercel-hosted deployments are automatically mitigated.

CVSS severity7.5
High
EPSS probability3.96%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in Next.js 9.5.5 through 14.2.14 allows remote attackers to access protected root-level pages. The server accepts unvalidated __nextLocale query values and normalizes the request pathname differently from the path evaluated by authorization middleware. Exposure requires a self-hosted affected application that bases authorization on middleware pathname checks; Vercel-hosted deployments are automatically mitigated.

The record

CVE
CVE-2024-51479
Published
Dec 17, 2024
Updated
Dec 17, 2024
Vendor
Vercel
Product
Next.js
Classifications
CWE-285, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 17, 2024CVE publishedPublication date reported by the CVE source.
  2. Dec 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 9.5.5, < 14.2.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Vercel · Next.jsversion=>= 9.5.5, < 14.2.15

Published CVSS scores

7.5Vercel GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-285Improper Authorization
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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