CVE-2025-29927

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.

CVSS: 9.1Criticalscored by the publisher (CNA)
Exploited in the wild: Not knownPublic exploit code; not in CISA KEV
EPSS: 99.2%chance of exploitation in the next 30 daystop 0.1% of scored CVEsFIRST score of 11 Nov 2026
Fix: Patch availablesee the advisories in the references
Published: 21 Mar 2025analysed here 12 Nov 2026

Summary

Triage

Attack surface: Server-side
Exploitable: At runtime
Attack vector: network
Weaknesses: CWE-285 Common Weakness
CWE-863 Incorrect Authorization
Can a WAF block it?: Partly. See why

The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.

Affected products

Product	Affected versions	Vendor says fixed in
vercel next.js	>= 11.1.4 and < 12.3.5>= 14.0.0 and < 14.2.25>= 15.0.0 and < 15.2.3>= 13.0.0 and < 13.5.9Vendor says fixed in: not stated	Not stated by the vendor

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

Products named in our analysis

vercel:next.js

Fix and mitigation

WAF and other mitigations

Can a WAF block it? Partly. Cloudflare publishes WAF rules written for this CVE. Such rules block the known exploit requests and buy time, but attackers can change the request to get past them, so they do not replace the patch.

Cloudflare · 3 rules (Disabled) · since 22 Mar 2025
- Next.js - Auth Bypass - CVE:CVE-2025-29927 · Cloudflare Managed Ruleset
- Workers, Pages, WAF - New Managed WAF rule for Next.js CVE-2025-29927.
- Next.js - Auth Bypass - CVE:CVE-2025-29927 - 2 · Cloudflare Managed Ruleset

Also consider: patch · enable the vendor rule in block mode · per-resource ACL

Based on WAF vendor rules published for this CVE. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.

Remediation steps (AI-written)

Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.

Exploitation evidence

CISA KEV catalog: Not listed as of our last sync.
Public exploit code: Yes: 1 on Exploit-DB · 1 Metasploit module · 129 GitHub proofs of concept · 1 Nuclei template
CISA SSVC: exploitation none, automatable yes, technical impact totalAssessed by CISA 8 Apr 2025 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.

Exploit-DB

Next.js Middleware 15.2.2 - Authorization Bypasswebapps, 5 Apr 2025

Metasploit

auxiliary/scanner/http/nextjs_middleware_auth_bypassauxiliary, rank normal

Nuclei

Next.js Middleware Bypassdetection template, critical

GitHub proofs of concept

aydinnyunus/CVE-2025-29927102 stars
AnonKryptiQuz/NextSploit92 stars
websecnl/CVE-2025-29927-PoC-Exploit20 stars
6mile/nextjs-CVE-2025-2992719 stars

and 125 more repositories

Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.

Timeline

21 Mar 2025Published
22 Mar 2025First public exploit or proof of conceptsame day later
8 Apr 2025CISA SSVC assessment: exploitation none18 days later
8 Apr 2025CVE record last updatedsame day later
12 Nov 2026Analysed by vulneraibility.com583 days (about 2 years) later

CVSS vector

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

Metric	Value	What it means
Attack vector	NetworkReachable over the internet or any routable network.	Reachable over the internet or any routable network.
Attack complexity	LowRepeatable attack, no special conditions.	Repeatable attack, no special conditions.
Privileges required	NoneThe attacker needs no prior access.	The attacker needs no prior access.
User interaction	NoneNo victim action needed.	No victim action needed.
Scope	UnchangedImpact stays within the vulnerable component.	Impact stays within the vulnerable component.
Confidentiality	HighTotal data disclosure possible.	Total data disclosure possible.
Integrity	HighComplete modification possible.	Complete modification possible.
Availability	NoneThe service stays up.	The service stays up.

Common questions

Is CVE-2025-29927 being exploited?

Not confirmed. CVE-2025-29927 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 99% probability of exploitation in the next 30 days.

How severe is CVE-2025-29927?

CVE-2025-29927 is rated Critical with a CVSS score of 9.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2025-29927?

Yes. A fix has been recorded for CVE-2025-29927. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2025-29927 affect?

CVE-2025-29927 affects vercel:next.js. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

References

NVD CVE.org CVE Details Source

8 references in the CVE record, grouped by the tags the record gives them.

Where the data on this page comes from

CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
NVD: CVSS and CPE data
CISA Vulnrichment (ADP): SSVC decision points
FIRST EPSS: exploit probability and percentile
Exploit-DB: published exploits
Metasploit Framework: exploit and scanner modules
Nuclei templates: detection templates
PoC-in-GitHub: GitHub repositories that claim a proof of concept

Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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