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Next.js EUVDEUVD-2026-25632

| CVE-2026-41248 CRITICAL
Interpretation Conflict (CWE-436)
2026-04-24 GitHub_M GHSA-vqx2-fgx2-5wq9
9.1
CVSS 3.1 · GitHub Advisory
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V4 - API and Web Service Interpretation consistency
Act Now Prioritize within 24-48h. Why: CRITICAL severity.
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Jul 24, 2026

Authentication/authorization bypass in Clerk's official JavaScript SDKs (@clerk/nextjs, @clerk/nuxt, @clerk/astro, and the underlying @clerk/shared) allows unauthenticated remote attackers to defeat middleware-based route protection: a crafted request evades createRouteMatcher so that clerkMiddleware never invokes auth.protect(), letting the request reach protected downstream handlers such as API routes and server components. Sessions are not compromised and no user is impersonated — only the middleware gating decision is bypassed — so real impact is confined to apps that rely solely on middleware gating without redundant checks in their handlers. CVSS is 9.1 and SSVC rates technical impact as total, but there is no public exploit identified at time of analysis and EPSS is low at 0.09% (26th percentile).

Affected VersionsENISA

shared 3.0.0-canary.v20250225091530, < 3.47.4
astro 3.0.0, < 3.0.15
nextjs 6.0.0-snapshot.vb87a27f, < 6.39.2
astro 0.0.1, < 1.5.7
nuxt 1.1.0, < 1.13.28
shared 4.0.0, < 4.8.1
shared 2.20.17, < 2.22.1
astro 2.0.0-snapshot.v20241206174604, ≤ 2.17.9
nextjs 7.0.0, < 7.2.1
nuxt 2.0.0, < 2.2.2
nextjs 5.0.0, < 5.7.6

Affected Packages

npm @clerk/astro fix: 1.5.7, 2.17.10, 3.0.15
npm @clerk/nextjs fix: 5.7.6, 6.39.2, 7.2.1
npm @clerk/nuxt fix: 1.13.28, 2.2.2
npm @clerk/shared fix: 2.22.1, 3.47.4, 4.8.1
euvd astro_0_0_1 fix: 1.5.7
euvd astro_2_0_0_snapshot_v20241206174604 no fix
euvd astro_3_0_0 fix: 3.0.15
euvd nextjs_5_0_0 fix: 5.7.6
euvd nextjs_6_0_0_snapshot_vb87a27f fix: 6.39.2
euvd nextjs_7_0_0 fix: 7.2.1
euvd nuxt_1_1_0 fix: 1.13.28
euvd nuxt_2_0_0 fix: 2.2.2
euvd shared_2_20_17 fix: 2.22.1
euvd shared_3_0_0_canary_v20250225091530 fix: 3.47.4
euvd shared_4_0_0 fix: 4.8.1

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 15 packages in npm, euvd

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 9.1 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

Lifecycle Timeline

3
Patch released
Apr 29, 2026 - 20:56 nvd
Patch available
Patch available
Apr 24, 2026 - 23:02 EUVD
CVE Published
Apr 24, 2026 - 21:04 nvd
CRITICAL 9.1

DescriptionGitHub Advisory

Clerk JavaScript is the official JavaScript repository for Clerk authentication. createRouteMatcher in @clerk/nextjs, @clerk/nuxt, and @clerk/astro can be bypassed by certain crafted requests, allowing them to skip middleware gating and reach downstream handlers. This vulnerability is fixed in @clerk/astro 1.5.7, 2.17.10, and 3.0.15; @clerk/nextjs 5.7.6, 6.39.2, and 7.2.1; @clerk/nuxt 1.13.28 and 2.2.2; and @clerk/shared 2.22.1, 3.47.4, anc 4.8.1

Executive ViewAI

Why It Matters

Clerk's popular JavaScript authentication SDKs (@clerk/nextjs, @clerk/nuxt, @clerk/astro) have a critical security vulnerability that permits unauthorized access to protected application routes. Organizations using these libraries could face data exposure or unauthorized feature access if their implementations rely on Clerk's middleware alone for access control. Immediate update and validation of application architecture is required.

Recommended Action

Within 24 hours, inventory all applications using Clerk's JavaScript SDKs and categorize which routes depend solely on middleware-based authentication without additional handler-level validation. Within 7 days, apply Clerk's released security patch to @clerk/nextjs, @clerk/nuxt, @clerk/astro, and @clerk/shared per the vendor advisory, then redeploy all affected applications. Within 30 days, perform a comprehensive audit to ensure all protected endpoints implement defense-in-depth controls with authentication checks at multiple layers.

Business Impact: High
Compensating Controls

Apply vendor patch. As interim mitigation during deployment, implement redundant authentication validation in application handlers.

Threat Intelligence Overview

EPSS Score
0.1%
Top 74% exploitable
Threat Intel
1
1 source
Social Media
3
Sightings
Data Quality
7 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment GHSA CIRCL GitHub VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

46
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +46
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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