CVE-2026-12378
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 · uneditedThe Appointment Booking Calendar Plugin and Scheduling Plugin WordPress plugin through 1.1.28 does not validate data before passing it to a PHP deserialization function, allowing unauthenticated attackers to inject arbitrary PHP objects; where a suitable gadget chain is present on the site this can be leveraged to achieve remote code execution.
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 confidenceThe WordPress Appointment Booking Calendar plugin through version 1.1.28 suffers from a PHP object injection vulnerability due to improper input validation before passing data to a deserialization function. Unauthenticated attackers can inject arbitrary PHP objects, and when a suitable gadget chain exists on the target WordPress site, this can be weaponized for remote code execution.
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
- High
CVSS:3.1/AV:N/AC:H/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 checksWork through these to decide whether this CVE applies to you.
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Confirm WordPress installation existsVerify the site runs on WordPress by checking for wp-load.php or wp-config.php in the web root, or by accessing the wp-admin login page.Affected if WordPress is installed and the plugin is present
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Locate the plugin installationCheck the wp-content/plugins/ directory for a folder named 'appointment-booking-calendar', 'abc', or similar naming convention for the Appointment Booking Calendar plugin.Affected if The plugin directory exists in the WordPress plugins folder
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Identify installed plugin versionOpen the main plugin PHP file (typically named plugin-name.php) and locate the version comment in the file header, or check the readme.txt file for the 'Stable tag' entry.Affected if The reported version is 1.1.28 or any earlier version number
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Verify vulnerable code path existsSearch the plugin source code for calls to unserialize() that process user-supplied input without prior sanitization, particularly on parameters that can be reached without authentication.Affected if An unserialize() call processes input from unauthenticated requests without validation
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Confirm plugin is activeIn WordPress admin, go to Plugins > Installed Plugins and verify the Appointment Booking Calendar plugin is activated, or query the wp_options table for the active_plugins entry.Affected if The plugin is enabled and accessible to unauthenticated users
You are affected if the plugin is installed and the installed version is 1.1.28 or earlier, with the vulnerable unserialize() code path present and the plugin active.
Generated from the published advisory. Verify against your own configuration.
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 dataUpdate the plugin to a version that implements proper input validation and avoids unsafe PHP deserialization, or replace the unserialize() call with safe alternatives like JSON encoding.
- Consultation4.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,392.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-12378 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-12378 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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