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PHP File Inclusion (RFI/LFI)Weakness · CWE-98

CVE-2021-47900

CRITICAL · 9.8 CVSS v3.1 Published 2026-01-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Public exploit 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
Gila CMS versions prior to 2.0.0 contain a remote code execution vulnerability that allows unauthenticated attackers to execute arbitrary system commands through manipulated HTTP headers. Attackers can inject PHP code in the User-Agent header with shell_exec() to run system commands by sending crafted requests to the admin endpoint.

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

Gila CMS versions prior to 2.0.0 allow unauthenticated remote code execution via the User-Agent HTTP header. Attackers inject PHP code containing shell_exec() functions through crafted requests to the admin endpoint, bypassing authentication to execute arbitrary system commands on the server.

MitigationUpgrade Gila CMS to version 2.0.0 or later to receive the patched code that properly sanitizes HTTP headers and prevents PHP code injection via User-Agent.

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

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

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. Locate Gila CMS installation
    Search for gila CMS files in common web directories (e.g., /var/www/html, /home/*/public_html) or check for the presence of core Gila files like index.php, config.php, or a 'gila' directory.
    Affected if Gila CMS files are found in the web root.
  2. Identify installed Gila CMS version
    Check the version file or header. Gila CMS typically stores version information in a version.php file or displays it in the admin dashboard under 'System > Info' or similar.
    Affected if The identified version is below 2.0.0 (e.g., 1.x.x series).
  3. Verify admin endpoint accessibility
    Attempt to access the admin login page (typically /admin or /gila/admin) via HTTP request. Check if the endpoint responds without authentication.
    Affected if The admin login page loads without requiring authentication or is accessible externally.
  4. Check User-Agent header processing
    Send a test HTTP request to the admin endpoint with a crafted User-Agent header containing a simple PHP function call (e.g., 'User-Agent: <?php phpinfo(); ?>') and observe if the header value is reflected in server response or logs without sanitization.
    Affected if The User-Agent header content is reflected in the response or application logs without encoding or filtering.

The environment is affected if Gila CMS version is below 2.0.0 and the admin endpoint is accessible, allowing unauthenticated injection of PHP code via the User-Agent header.

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

Upgrade Gila CMS to version 2.0.0 or later to receive the patched code that properly sanitizes HTTP headers and prevents PHP code injection via User-Agent.

Recommended fix High confidence

Gila CMS 2.0.0

  1. 1. Back up the entire Gila CMS installation directory and database before proceeding with any changes
  2. 2. Download Gila CMS version 2.0.0 or later from the official source at gilacms.com or the official GitHub repository
  3. 3. Replace the existing Gila CMS files with the new version 2.0.0 files, preserving any custom configuration if required
  4. 4. Run any available database migration scripts included in the upgrade package
  5. 5. Verify the upgrade was successful by accessing the admin panel
  6. 6. Test that the vulnerability is patched by confirming the User-Agent header is no longer processed through shell_exec()
Caveat Review release notes for 2.0.0 to check for any configuration or feature changes that may affect your deployment

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

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,950
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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-2021-47900 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data