CVE-2026-34076

Clerk JavaScript: SSRF in the opt-in clerkFrontendApiProxy feature may leak secret keys to unintended host

State: Published
Severity: 7.4 High
Published: Apr 1, 2026
Updated: Apr 1, 2026
Reserved: Mar 25, 2026

Description

Clerk JavaScript is the official JavaScript repository for Clerk authentication. In @clerk/hono from versions 0.1.0 to before 0.1.5, @clerk/express from versions 2.0.0 to before 2.0.7, @clerk/backend from versions 3.0.0 to before 3.2.3, and @clerk/fastify from versions 3.1.0 to before 3.1.5, the clerkFrontendApiProxy function in @clerk/backend is vulnerable to Server-Side Request Forgery (SSRF). An unauthenticated attacker can craft a request path that causes the proxy to send the application's Clerk-Secret-Key to an attacker-controlled server. This issue has been patched in @clerk/hono version 0.1.5, @clerk/express version 2.0.7, @clerk/backend version 3.2.3, and @clerk/fastify version 3.1.5.

Scores

CVSS	Score	Vector	Source
3.1	7.4 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N	GitHub_M

Weaknesses

CWE-918 Server-Side Request Forgery (SSRF)

Affected Products

Product	Versions
javascriptclerk	@clerk/hono >= 0.1.0, < 0.1.5Affected @clerk/express >= 2.0.0, < 2.0.7Affected @clerk/backend >= 3.0.0, < 3.2.3Affected @clerk/fastify >= 3.1.0, < 3.1.5Affected

References

https://github.com/clerk/javascript/security/advisories/GHSA-gjxx-92w9-8v8f

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