---
id: "CVE-2026-111727"
kind: "vulnerability"
aliases: ["CVE-2026-111727"]
title: "WordPress Appointment Booking Calendar plugin: stored XSS via vs_text_submitbtn"
severity: "medium"
cvss: 6.4
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["package", "self-hosted", "wordpress", "wordpress-plugin"]
not_affected_if: ["plugin-not-installed", "plugin-updated"]
published_at: "2026-10-28T04:17:57+00:00"
first_seen_at: "2026-10-28T04:30:58+00:00"
updated_at: "2026-10-28T04:32:03+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-111727", "first_seen_at": "2026-10-28T04:30:58+00:00"}]
---

# WordPress Appointment Booking Calendar plugin: stored XSS via vs_text_submitbtn

The Appointment Booking Calendar WordPress plugin, through version 1.4.05, does not sanitize the vs_text_submitbtn parameter, so stored script can be injected into pages. Visitors who open an injected page run the attacker's script in their browser.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check whether the Appointment Booking Calendar plugin is installed and its version is `1.4.05` or lower
- Review which users are listed as calendar owners in the plugin's calendar list screen
- unknown whether the sources give a specific file or setting to inspect

## Fix

- Update the Appointment Booking Calendar plugin to a version later than `1.4.05`
- Remove calendar owner assignments from accounts that do not need them
- unknown whether a patched version number is given in the sources

## Timeline

- 2026-10-28T04:30:58+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-111727

## From the sources

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.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_