CVE-2026-34076Network attack vector

Secret-key disclosure via crafted proxy path

Published Apr 1, 2026 · Updated Apr 1, 2026

SSRF in affected Clerk JavaScript SDK packages allows remote attackers to expose an application's Clerk Secret Key through a crafted path. The clerkFrontendApiProxy function accepts a request path containing repeated slashes and forwards the Clerk-Secret-Key to the unintended host. Exploitation requires an affected package and the nondefault frontendApiProxy feature to be enabled; @clerk/nextjs is not affected.

CVSS severity7.4
High
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in affected Clerk JavaScript SDK packages allows remote attackers to expose an application's Clerk Secret Key through a crafted path. The clerkFrontendApiProxy function accepts a request path containing repeated slashes and forwards the Clerk-Secret-Key to the unintended host. Exploitation requires an affected package and the nondefault frontendApiProxy feature to be enabled; @clerk/nextjs is not affected.

The record

CVE
CVE-2026-34076
Published
Apr 1, 2026
Updated
Apr 1, 2026
Vendor
Clerk
Product
Clerk JavaScript SDK
Classifications
CWE-918, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=@clerk/backend >= 3.0.0, < 3.2.3
  2. Affected versionversion=@clerk/express >= 2.0.0, < 2.0.7
  3. Affected versionversion=@clerk/fastify >= 3.1.0, < 3.1.5
  4. Affected versionversion=@clerk/hono >= 0.1.0, < 0.1.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Clerk · Clerk JavaScript SDKversion=@clerk/backend >= 3.0.0, < 3.2.3; version=@clerk/express >= 2.0.0, < 2.0.7; version=@clerk/fastify >= 3.1.0, < 3.1.5; version=@clerk/hono >= 0.1.0, < 0.1.5

Published CVSS scores

7.4GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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