Caddy SecurityWeb server / proxy · Greenpau

CVE-2024-21494

MEDIUM · 5.4 CVSS v3.1 Published 2024-02-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
61/100
Remediation priority · Elevated
Remotely reachable No privileges

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
All versions of the package github.com/greenpau/caddy-security are vulnerable to Authentication Bypass by Spoofing via the X-Forwarded-For header due to improper input sanitization. An attacker can spoof an IP address used in the user identity module (/whoami API endpoint). This could lead to unauthorized access if the system trusts this spoofed IP address.

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 · moderate confidence

All versions of github.com/greenpau/caddy-security have improper input sanitization of the X-Forwarded-For header, allowing attackers to spoof IP addresses in the /whoami API endpoint. If downstream systems trust this spoofed IP for authentication or authorization decisions, unauthorized access may occur.

MitigationImplement strict validation of X-Forwarded-For headers, preferably by only trusting the header from trusted proxies and adding anti-spoofing measures such as validating IP format and rejecting obviously spoofed values.

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

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Caddy SecurityWeb server / proxy
Affected:all versions

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
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/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 if caddy-security is deployed
    Check for go.mod containing 'github.com/greenpau/caddy-security' or look for the binary/plugin in the Caddy configuration
    Affected if The product is present in the environment
  2. Confirm the /whoami endpoint exists
    Check if the /whoami route is registered in the Caddyfile or programmatic configuration (search for 'whoami' or the path handler)
    Affected if The /whoami endpoint is exposed and accessible
  3. Verify X-Forwarded-For header handling
    Inspect the source code or configuration to see if the X-Forwarded-For header is read and used without validation. Look for header extraction logic in the whoami handler.
    Affected if The application processes X-Forwarded-For without sanitization or anti-spoofing checks
  4. Check if IP is used for auth decisions
    Review downstream systems or application logic to see if the client IP (potentially from X-Forwarded-For) is used for authentication or authorization
    Affected if The IP from the header is trusted for access control decisions without additional verification

If caddy-security with the /whoami endpoint is in use and the X-Forwarded-For header is trusted for authentication or authorization, the environment is affected by this vulnerability.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement strict validation of X-Forwarded-For headers, preferably by only trusting the header from trusted proxies and adding anti-spoofing measures such as validating IP format and rejecting obviously spoofed values.

Fix this in Caddy Security Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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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-2024-21494 in production — separate from our analysis above.

No notes yet

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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
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