vciy

CVE-2025-29927

INDEX BUILT · 2026-09-20

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Authorization Bypass in Next.js Middleware

CVE-2025-299274 of 4 sources documented this
60

rank 60 = 30 + 23 + 2 + 5 + 0

rank@v1 · this cycle

Someone is already using it

CISA KEV catalog · public proof-of-concept · FIRST EPSS

EPSS 0.99225  ·  without this subject the record ranks 30

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 9.1, from the CNA  ·  without this subject the record ranks 37

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

rose on 2025-11-21  ·  without this subject the record ranks 58

How much of the world it touches

NVD CPE configurations

4 products in the CPE ranges  ·  without this subject the record ranks 55

Someone else already set the date

CISA KEV remediation due date

no CISA due date  ·  without this subject the record ranks 60

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$4.36Mover the next 30 days, if this record is yours
Movement+$447,000on 2025-11-21, the last material move, 9 months before this reading
Basisassumeda published average, not your estate

$4.36M = $4.99M incident cost x 0.8814887365328109 exposure x 0.99225 likelihood

udv@v1 · unaudited · wrong for you until you say what you run

$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.

Hindsight · the state

0.99225EPSSNOT IN KEVas of 2026-09-20
Severity9.1 CRITICALreceipt
Harmunauthenticated · networkreceipt
Exploitationpublic proof-of-conceptreceipt
Defenseunaffected versions publishedreceipt
Movementdoubled within 72hreceipt
PLATEAU10Minimal movement since 2025-11-21, 280 days at 0.99, as of 2026-08-28. arc-rules@v1

Foresight · where to check next

QNAP Systems Inc.Google Android29927

This record is one instance of CWE-285, improper authorization. The index holds 1650 prior instances of this class, 2 KEV-listed. The nearest of its KEV-listed records are drawn beside this. taxonomy@v1

Full pattern panel

Prior records in this weakness class. Each is its own record, dated and receipted.
Color is a claim, not decoration:the hostile worldthe defenseno signalspoke length is how much of the record matches, not how bad it is

Running vercel next.js? Check your version

A deterministic range check against the ranges this record publishes. It tells you where a version sits in the record, not whether your deployment is exploitable. No account needed.

Watch this record

Matches your own product list against every record this index holds, and tells you when one of them moves.

What counts as a move

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Record your call

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Harm, if it fires from the vector and the weakness

Written for the ticket you're about to file.

Reachnetwork-reachable · no privileges required · no user interaction · low attack complexityreceipt
ImpactComplete confidentiality and integrity lossreceipt
Scored fromCVSS v3.1 · the CNA's vectorreceipt
Weakness classCWE-285 Improper Authorizationreceipt
Published consequencesCWE-285: Confidentiality: Read Application Data, Read Files or Directories; Integrity: Modify Application Data, Modify Files or Directories…[email protected]

CISA KEV & Federal Remediation Deadline from the record and CISA

The fix, and how long it's been waiting.

First unaffected version, by branchnext.js 12.3.5; next.js 13.5.9; next.js 14.2.25; next.js 15.2.3receipt
Patch available sinceNo dated patch-availability record in held sources. The index holds reference URLs without dates and only the current revision of the CVE record, so the day a fix first existed cannot be derived. Only the versions it landed in.

Exploit Status & Known PoCs a ladder, not a score

Current rung: Proof-of-concept published · 119 public repositories, 2025-03-22.

  • RUNG 1Nothing observed in held sources
  • RUNG 2Proof-of-concept published · 119 public repositories2025-03-22receipt
  • RUNG 3Exploited in the wild · CISA KEV listed
  • RUNG 4Ransomware campaign use known

Authority who says so

CVSS, the CNA9.1 CRITICALreceipt
Exploit probability0.99225 · top 0.07% of all CVEsreceipt
Blast breadth1 product across 1 vendorderived
Assigned byGitHub_Mreceipt
Recorded changes90 · last 16 Sep 2026derived

Affected & Fixed Versions as published

Affected productvercel next.jsreceipt
Published rangesvercel next.js >= 11.1.4 < 12.3.5; vercel next.js >= 13.0.0 < 13.5.9; vercel next.js >= 14.0.0 < 14.2.25; vercel next.js >= 15.0.0 < 15.2.3receipt

A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.

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Attack path

Unauthenticated network requestno credentials, no interactionvercel next.jsCWE-285 weaknessConfidentiality and integrity lossC:H / I:Hexploits CWE-285data compromise

What it is stated by the CNA

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. receipt

NVD's analysis a second authority

weakness
CWE-285; CWE-863
affected versions
vercel next.js >= 11.1.4 < 12.3.5; vercel next.js >= 13.0.0 < 13.5.9; vercel next.js >= 14.0.0 < 14.2.25; and 1 more, listed in full below
also scored by
[email protected] 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

check it yourself github.com github.com github.com github.com github.com receipt

Dated events

2025-03-24EPSS moved 0.00 to 0.322025-03-27EPSS moved 0.51 to 0.832026-06-22EPSS moved 0.93 to 0.98

Movement the material steps

22 Mar 20250.0003
24 Mar 20250.3208 · crossed 0.10
25 Mar 20250.49792
26 Mar 20250.50729 · crossed 0.50
27 Mar 20250.83133
15 Apr 20250.91416 · crossed 0.90
18 Nov 20250.82784 · crossed 0.90
21 Nov 20250.92947 · crossed 0.90
15 Jun 20260.93247 · scoring model v2026.06.15
28 Aug 20260.99225

This score more than doubled inside 72 hours. Both observations are in the full history below.

Show all 87 observations
22 Mar 20250.0003
23 Mar 20250.00163
24 Mar 20250.3208
25 Mar 20250.49792
26 Mar 20250.50729
27 Mar 20250.83133
29 Mar 20250.84753
30 Mar 20250.847
6 Apr 20250.85633
8 Apr 20250.89103
9 Apr 20250.89241
15 Apr 20250.91416
21 Apr 20250.91895
22 Apr 20250.92557
1 May 20250.92053
4 May 20250.92557
5 May 20250.92434
11 May 20250.92645
15 May 20250.92198
17 May 20250.91964
20 May 20250.93113
28 May 20250.93156
1 Jun 20250.93075
3 Jun 20250.93199
4 Jun 20250.93156
20 Jun 20250.93638
25 Jun 20250.93721
27 Jun 20250.93638
1 Jul 20250.93584
4 Jul 20250.93638
16 Jul 20250.93721
17 Jul 20250.93638
21 Jul 20250.93601
1 Aug 20250.93631
4 Aug 20250.93601
14 Aug 20250.93549
1 Sep 20250.93706
4 Sep 20250.93549
11 Sep 20250.92084
1 Oct 20250.91603
4 Oct 20250.92084
17 Oct 20250.92593
18 Oct 20250.92084
1 Nov 20250.91603
4 Nov 20250.92084
5 Nov 20250.9253
13 Nov 20250.93093
14 Nov 20250.92947
15 Nov 20250.9253
18 Nov 20250.82784
21 Nov 20250.92947
23 Nov 20250.9253
1 Dec 20250.91603
4 Dec 20250.9253
18 Dec 20250.93093
19 Dec 20250.92947
20 Dec 20250.9253
24 Dec 20250.93093
25 Dec 20250.93239
27 Dec 20250.92896
1 Jan 20260.92365
4 Jan 20260.92896
1 Feb 20260.92324
4 Feb 20260.92896
18 Feb 20260.9319
20 Feb 20260.92896
1 Mar 20260.92324
3 Mar 20260.92784
4 Mar 20260.93238
5 Mar 20260.92955
21 Apr 20260.93238
24 Apr 20260.92955
26 Apr 20260.93114
29 Apr 20260.91848
1 May 20260.92118
8 May 20260.92057
10 May 20260.92306
11 May 20260.92118
22 May 20260.92306
23 May 20260.9255
25 May 20260.92118
15 Jun 20260.93247
22 Jun 20260.98378
24 Jun 20260.99621
9 Jul 20260.99301
17 Aug 20260.99278
28 Aug 20260.99225

87 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt

The full biography

EPSS 0.99225Published2025-03-21Public PoC2025-03-22Index as of2026-08-28

Exploit probability more than doubled between 2025-03-22 and 2025-03-23 (0.0003 → 0.00163) and the record had been public for 1 year, 5 months when this index was last written.

Published 2025-03-21 receipt · Public PoC 2025-03-22 receipt · Index as of 2026-08-28 derived

The pattern, elsewhere

This record is one instance of CWE-285, improper authorization. The index holds 1650 prior instances of this class, 2 KEV-listed. The nearest of its KEV-listed records are drawn beside this. [email protected]

CVE-2021-28799 · QNAP Systems Inc. HBS 3matches 6 of 10KEV listed · 2021receipt
CVE-2026-58704 · Google Androidonly 2 attributes comparableKEV listed · 2026receipt

"Matches n of m" counts the attributes the two records can both be compared on: the CVSS metrics they share a version of, any weakness class beyond this one, and the vendor. fit-rules@v1

1650 records in this class held. The six above are drawn from the ones CISA has listed as exploited, ranked by how much of the record matches this one. That is why every one of them is KEV-listed: the pool is, so the colour on those spokes says nothing the pool has not already said.

No curated product neighbourhood is held for this product, so the records above are the nearest this index can name. The neighbourhood table covers a small set of products and is extended by hand.

Siblings and hubs

Records related to this one

Its defect family

vercel next.js

Of the 3 records in this family that state one, this holds the highest EPSS percentile: 0.99933.

Grouped by shared product and weakness, not by shared vulnerability. Each record's own state is on its own page.

Family membership: held values

This record is one of a group, and the group's page describes all of them. This page is kept and dated, and the defect family's own page is the one we offer for indexing: the whole group.

Browse the index from here

These are index-wide views, not findings about CVE-2025-29927.

What usually comes next

Everything above needs no account. What is below is work: assembling it, scoping it to your estate, watching it, and handing it to someone else.

Everything on this page is free. Public data. Withholding it protects nothing.