Deserialization of Untrusted DataWeakness · CWE-502

CVE-2025-39503

CRITICAL · 9.8 CVSS v3.1 Published 2025-05-23
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
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
Deserialization of Untrusted Data vulnerability in GoodLayers Goodlayers Hotel gdlr-hotel allows Object Injection.This issue affects Goodlayers Hotel: from n/a through <= 3.1.4.

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

A deserialization vulnerability in the GoodLayers Hotel plugin (gdlr-hotel) for WordPress allows remote attackers to inject malicious PHP objects via untrusted data. This object injection can potentially lead to arbitrary code execution, file inclusion, or SQL injection depending on available 'magic methods' in the plugin or other installed plugins/themes.

MitigationUpdate the GoodLayers Hotel plugin to the latest patched version immediately. If no patched version is available, disable and remove the plugin until a fix is released, as the CVSS 9.8 indicates critical exploitable conditions.

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. Confirm GoodLayers Hotel plugin installation
    Navigate to WordPress admin dashboard > Plugins > Installed Plugins. Look for 'GoodLayers Hotel' or 'gdlr-hotel' in the list of installed plugins.
    Affected if Plugin is present in the plugins list
  2. Identify installed plugin version
    In the Plugins list, click on the plugin name or view the plugin details to find the version number. Alternatively, inspect the plugin header in /wp-content/plugins/gdlr-hotel/ folder via file manager or FTP.
    Affected if Version number is visible and can be compared to patched version
  3. Verify plugin is active
    In WordPress admin > Plugins, check if the GoodLayers Hotel plugin shows as 'Active'. Inactive plugins may still have vulnerable code but are not actively exploitable.
    Affected if Plugin status shows as Active
  4. Check for suspicious PHP object injection patterns
    Review web server access logs for unusual serialized data patterns in POST/GET requests to the site. Look for patterns containing 'O:' or 'a:' followed by numbers, which indicate PHP object serialization.
    Affected if Unusual serialized data found in request logs pointing to the site
  5. Inspect for unauthorized admin users or file changes
    In WordPress admin > Users, check for unexpected administrator accounts. Via FTP/file manager, inspect plugin files for recently modified PHP files in the gdlr-hotel directory.
    Affected if New admin accounts exist or plugin files were recently modified without your knowledge

User is affected if the GoodLayers Hotel plugin is installed, active, and running an unpatched version susceptible to PHP object injection attacks.

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

Update the GoodLayers Hotel plugin to the latest patched version immediately. If no patched version is available, disable and remove the plugin until a fix is released, as the CVSS 9.8 indicates critical exploitable conditions.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,290
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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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-2025-39503 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