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Fencer Vulns
high 8.1

CVE-2026-42349 json

Clerk: Authorization bypass when combining organization, billing, or reverification checks

published 2026-04-30 6 mo ago modified 2026-10-26 13 d ago also GHSA-w24r-5266-9c3c , EUVD-2026-29125

cvss
8.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

Clerk JavaScript is the official JavaScript repository for Clerk authentication. has(), auth.protect(), and related authorization predicates in @clerk/shared, @clerk/nextjs, @clerk/backend, and other framework SDKs can return true for certain combined authorization checks when the result should be false, allowing a gated action to proceed for a user who does not satisfy the full set of requested conditions. This call shape can be bypassed if certain conditions are met: a has() or auth.protect() call that combines a reverification check with any of role, permission, feature, or plan, or that combines a billing check (feature or plan) with a role or permission check. This vulnerability is fixed in @clerk/clerk-js 5.125.10 and 6.7.5.

Patch / fix

  • npm @clerk/shared 3.47.5, 4.8.3
  • npm @clerk/backend 2.33.3, 3.2.14
  • npm @clerk/nextjs 6.39.3, 7.2.4
  • npm @clerk/clerk-js 5.125.10, 6.7.5
  • npm @clerk/clerk-react 5.61.6
  • npm @clerk/react 6.4.3
  • npm @clerk/vue 1.17.21, 2.0.16
  • npm @clerk/astro 2.17.11, 3.0.18
  • npm @clerk/nuxt 1.13.29, 2.2.5
  • npm @clerk/clerk-expo 2.19.36
  • npm @clerk/expo 3.2.2
  • npm @clerk/react-router 2.4.13, 3.1.4
  • npm @clerk/tanstack-react-start 0.29.11, 1.1.4
  • npm @clerk/chrome-extension 2.9.15, 3.1.15
  • npm @clerk/fastify 2.6.31, 3.1.16
  • npm @clerk/express 1.7.79, 2.1.6
  • npm @clerk/hono 0.1.16
  • clerk clerk/astro 2.17.11, 3.0.18
  • clerk clerk/backend 2.33.3, 3.2.14
  • clerk clerk/chrome-extension 2.9.15, 3.1.15
  • clerk clerk/clerk-expo 2.19.36
  • clerk clerk/clerk-js 5.125.10, 6.7.5
  • clerk clerk/clerk-react 5.61.6
  • clerk clerk/expo 3.2.2
  • clerk clerk/express 1.7.79, 2.1.6
  • clerk clerk/fastify 2.6.31, 3.1.16
  • clerk clerk/hono 0.1.16
  • clerk clerk/nextjs 7.2.4
  • clerk clerk/nuxt 1.13.29, 2.2.5
  • clerk clerk/react 6.4.3

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/clerk/javascript/security/advisories/GHSA-w24r-5266-9c3c referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 7.6 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 4.0 7.6 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm @clerk/shared
>=3.0.0, <3.47.5
>=4.0.0, <4.8.3
3.47.5
4.8.3
npm @clerk/backend
>=2.0.0, <2.33.3
>=3.0.0, <3.2.14
2.33.3
3.2.14
npm @clerk/nextjs
>=6.0.0, <6.39.3
>=7.0.0, <7.2.4
6.39.3
7.2.4
npm @clerk/clerk-js
>=5.22.0, <5.125.10
>=6.0.0, <6.7.5
5.125.10
6.7.5
npm @clerk/clerk-react
>=5.9.0, <5.61.6
5.61.6
npm @clerk/react
>=6.0.0, <6.4.3
6.4.3
npm @clerk/vue
>=1.0.0, <1.17.21
>=2.0.0, <2.0.16
1.17.21
2.0.16
npm @clerk/astro
>=2.0.0, <2.17.11
>=3.0.0, <3.0.18
2.17.11
3.0.18
npm @clerk/nuxt
>=1.0.0, <1.13.29
>=2.0.0, <2.2.5
1.13.29
2.2.5
npm @clerk/clerk-expo
>=2.2.11, <2.19.36
2.19.36
npm @clerk/expo
>=3.0.0, <3.2.2
3.2.2
npm @clerk/react-router
>=0.0.1, <2.4.13
>=3.0.0, <3.1.4
2.4.13
3.1.4
npm @clerk/tanstack-react-start
>=0.0.1, <0.29.11
>=1.0.0, <1.1.4
0.29.11
1.1.4
npm @clerk/chrome-extension
>=1.3.5, <2.9.15
>=3.0.0, <3.1.15
2.9.15
3.1.15
npm @clerk/fastify
>=1.0.42, <2.6.31
>=3.0.0, <3.1.16
2.6.31
3.1.16
npm @clerk/express
>=0.1.0, <1.7.79
>=2.0.0, <2.1.6
1.7.79
2.1.6
npm @clerk/hono
>=0.0.2, <0.1.16
0.1.16

Affected products

  • clerk javascript
  • @clerk shared
  • @clerk backend
  • @clerk nextjs
  • @clerk clerk-react
  • @clerk react
  • @clerk vue
  • @clerk astro
  • @clerk nuxt
  • @clerk clerk-expo
  • @clerk expo
  • @clerk react-router
  • @clerk tanstack-react-start
  • @clerk chrome-extension
  • @clerk fastify
  • @clerk express
  • @clerk hono

Classification

Weakness
  • CWE-754 Improper Check for Unusual or Exceptional Conditions
  • CWE-863 Incorrect Authorization
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.