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Server-Side Request Forgery (SSRF)Weakness · CWE-918

CVE-2026-34076

HIGH · 7.4 CVSS v3.1 Published 2026-04-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
83/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The clerkFrontendApiProxy function in @clerk/backend is vulnerable to Server-Side Request Forgery (SSRF). An unauthenticated attacker can craft a malicious request path that causes the proxy to forward the application's Clerk-Secret-Key to an attacker-controlled server, resulting in complete credential theft.

MitigationUpdate affected Clerk packages (@clerk/hono to 0.1.5+, @clerk/express to 2.0.7+, @clerk/backend to 3.2.3+, @clerk/fastify to 3.1.5+) to the patched versions. Rotate any Clerk-Secret-Key that may have been exposed prior to patching.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed @clerk/backend version
    Run 'npm list @clerk/backend' or check your package.json for the @clerk/backend dependency version
    Affected if Version is lower than 3.2.3 (vulnerable range: all versions before patch)
  2. Identify installed @clerk/hono version
    Run 'npm list @clerk/hono' or check package.json if this package is used
    Affected if Version is lower than 0.1.5 and the package is installed
  3. Identify installed @clerk/express version
    Run 'npm list @clerk/express' or check package.json if this package is used
    Affected if Version is lower than 2.0.7 and the package is installed
  4. Identify installed @clerk/fastify version
    Run 'npm list @clerk/fastify' or check package.json if this package is used
    Affected if Version is lower than 3.1.5 and the package is installed
  5. Audit network logs for suspicious outbound requests
    Review application logs and network traffic for requests from your server to unknown external IPs, especially containing paths like '/api/v1/backend_api' forwarding the Clerk-Secret-Key header
    Affected if Any outbound requests to attacker-controlled servers containing your Clerk-Secret-Key are observed

Your environment is affected if any of the @clerk packages (@clerk/backend <3.2.3, @clerk/hono <0.1.5, @clerk/express <2.0.7, @clerk/fastify <3.1.5) are installed and the clerkFrontendApiProxy endpoint is exposed, or if your Clerk-Secret-Key has been leaked to an external server.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update affected Clerk packages (@clerk/hono to 0.1.5+, @clerk/express to 2.0.7+, @clerk/backend to 3.2.3+, @clerk/fastify to 3.1.5+) to the patched versions. Rotate any Clerk-Secret-Key that may have been exposed prior to patching.

Recommended fix High confidence

Upgrade to @clerk/[email protected], @clerk/[email protected], @clerk/[email protected], and @clerk/[email protected] or later

  1. Identify which Clerk packages (@clerk/hono, @clerk/express, @clerk/backend, or @clerk/fastify) are used in the application
  2. Run npm list to see current installed versions of affected Clerk packages
  3. Update @clerk/hono to version 0.1.5 or higher using: npm install @clerk/hono@^0.1.5
  4. Update @clerk/express to version 2.0.7 or higher using: npm install @clerk/express@^2.0.7
  5. Update @clerk/backend to version 3.2.3 or higher using: npm install @clerk/backend@^3.2.3
  6. Update @clerk/fastify to version 3.1.5 or higher using: npm install @clerk/fastify@^3.1.5
  7. Run npm install to install the updated packages
  8. Verify the installation was successful by checking the installed versions
Caveat Minor/patch version upgrades typically have no breaking changes; however, review release notes if upgrading across major versions

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
9.0 hours of engineering $1,570
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-34076 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data