What’s Vulnerable › Vulnerabilities
CVE-2026-34076: Clerk JavaScript: SSRF in the opt-in clerkFrontendApiProxy feature may leak secret keys to unintended host
- Severity: high (CVSS 7.4 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.3% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-04-01 · updated 2026-10-26
- Weakness: CWE-918
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.
Affected products
- clerk javascript: @clerk/hono >= 0.1.0, < 0.1.5, @clerk/express >= 2.0.0, < 2.0.7, @clerk/backend >= 3.0.0, < 3.2.3, @clerk/fastify >= 3.1.0, < 3.1.5
References
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