dbcve.org
Code InjectionWeakness · CWE-94

CVE-2025-12813

CRITICAL · 9.8 CVSS v3.1 Published 2025-11-11
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
The Holiday class post calendar plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 7.1 via the 'contents' parameter. This is due to a lack of sanitization of user-supplied data when creating a cache file. This makes it possible for unauthenticated attackers to execute code on the server.

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 Holiday class post calendar WordPress plugin (versions up to 7.1) is vulnerable to unauthenticated Remote Code Execution due to insufficient sanitization of the 'contents' parameter when creating cache files. Attackers can inject malicious PHP code into cache files through this parameter, achieving arbitrary code execution on the server.

MitigationUpdate the Holiday class post calendar plugin to version 7.2 or later which properly sanitizes user-supplied input before writing to cache files. Until patched, consider disabling the plugin or implementing web application firewall rules to block requests to the vulnerable cache-creation endpoint.

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 plugin is installed
    Navigate to WordPress admin dashboard, go to Plugins > Installed Plugins, and look for 'Holiday class post calendar' in the list of active plugins.
    Affected if The Holiday class post calendar plugin appears in the installed plugins list.
  2. Check installed version number
    In the Plugins list, find the Holiday class post calendar entry and note the version number displayed beneath the plugin name.
    Affected if The installed version is 7.1 or any version prior to 7.1.
  3. Locate plugin cache directory
    In your WordPress wp-content/plugins directory, look for a folder named 'holiday-class-post-calendar' or similar, and check for a 'cache' subdirectory within the plugin folder.
    Affected if A cache directory exists within the plugin folder.
  4. Inspect cache files for malicious PHP code
    Examine any .php files in the cache directory using a file editor or command line. Look for base64_decode, eval, shell_exec, system, or other suspicious PHP functions that were not expected from normal plugin operation.
    Affected if Any cache .php files contain encoded or obfuscated PHP code, or code that appears to be injected (such as unexpected system calls or shell commands).
  5. Review web server access logs
    Check your web server access logs (Apache, Nginx, or similar) for POST requests to the plugin's cache creation endpoint. Look for requests that include a 'contents' parameter with suspicious patterns.
    Affected if Log entries show unauthenticated requests to the plugin that include a 'contents' parameter with PHP code or encoded strings.

A user is affected if the Holiday class post calendar plugin is installed with version 7.1 or earlier, or if suspicious PHP files exist in the plugin's cache directory containing injected code.

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 the Holiday class post calendar plugin to version 7.2 or later which properly sanitizes user-supplied input before writing to cache files. Until patched, consider disabling the plugin or implementing web application firewall rules to block requests to the vulnerable cache-creation endpoint.

Recommended fix Moderate confidence

Plugin version 7.2 or later (verify exact fixed version from WordPress plugin repository)

  1. Navigate to the WordPress admin dashboard under Plugins > Installed Plugins
  2. Locate the 'Holiday Calendar' (or 'Holiday class post calendar') plugin
  3. Check the current version installed - if it is 7.1 or below, it is vulnerable
  4. Update the plugin to the latest available version (verify version 7.2 or higher contains the fix)
  5. Confirm the update completed successfully and test calendar functionality
Caveat Review plugin changelog for any configuration or feature changes between your current version and the upgrade version

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 / QA1.0 h
8.0 hours of engineering $1,390
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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-2025-12813 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