CVE-2026-34076

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

HIGH

7.4

CVSS Score

Published: April 1, 2026 at 04:59 PM UTC

Updated: October 26, 2026 at 10:10 PM UTC

1 product affected across 1 vendorJavaScript

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Severity

HIGH7.4

Exploit prediction

EPSS 0.3%

SSVC

No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

JavaScript · Clerknpm

90%

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

Affected range stops below 0.1.5, so it looks safe — our inference, not a vendor statement

Affected range stops below 2.0.7, so it looks safe — our inference, not a vendor statement

Affected range stops below 3.1.5, so it looks safe — our inference, not a vendor statement

Affected range stops below 3.2.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

x_refsource_CONFIRM

Source: cverecord

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

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.4HIGHGitHub_M

Attack Vector: NETWORK
Complexity: HIGH
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: HIGH
Integrity: HIGH
Availability: NONE

Vector?

Quick Info

StatusDEFERRED

CWE

CWE-918

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