@clerk/backend Performs Insufficient Verification of Data Authenticity

published 2025-07-09 16 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-20865 , GHSA-9mp4-77wg-rwx9

cvss: 7.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits: 0; none known

Clerk helps developers build user management. Applications that use the verifyWebhook() helper to verify incoming Clerk webhooks are susceptible to accepting improperly signed webhook events. The issue was resolved in @clerk/backend 2.4.0.

Patch / fix

fixed in 19

npm @clerk/backend 2.4.0
npm @clerk/astro 2.10.2
npm @clerk/express 1.7.4
npm @clerk/fastify 2.4.4
npm @clerk/nextjs 6.23.3
npm @clerk/nuxt 1.7.5
npm @clerk/react-router 1.6.4
npm @clerk/remix 4.8.5
npm @clerk/tanstack-react-start 0.18.3
clerk astro 2.10.2
clerk backend 2.4.0
clerk javascript 2.4.0
clerk express 1.7.4
clerk fastify 2.4.4
clerk nextjs 6.23.3
clerk nuxt 1.7.5
clerk react-router 1.6.4
clerk remix 4.8.5
clerk tanstack-react-start 0.18.3

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 16 mo ago (2025-07-09)

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
GitHub	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem	package	affected	fixed in
npm	@clerk/backend	>=2.0.0, <2.4.0	2.4.0
npm	@clerk/astro	>=2.9.0, <2.10.2	2.10.2
npm	@clerk/express	>=1.6.0, <1.7.4	1.7.4
npm	@clerk/fastify	>=2.3.0, <2.4.4	2.4.4
npm	@clerk/nextjs	>=6.2.10, <6.23.3	6.23.3
npm	@clerk/nuxt	>=1.7.0, <1.7.5	1.7.5
npm	@clerk/react-router	>=1.5.0, <1.6.4	1.6.4
npm	@clerk/remix	>=4.8.0, <4.8.5	4.8.5
npm	@clerk/tanstack-react-start	>=0.16.0, <0.18.3	0.18.3

Affected products

clerk javascript

Classification

Weakness

CWE-345 Insufficient Verification of Data Authenticity

References

github.com /clerk/javascript/security/advisories/GHSA-9mp4-77wg-rwx9
web
nvd.nist.gov /vuln/detail/CVE-2025-53548
advisory
github.com /clerk/javascript
package

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary