{
 "id": "WPSEC-2026-2885",
 "url": "https://wpsec.com/vuln/WPSEC-2026-2885/",
 "json_url": "https://wpsec.com/vuln/WPSEC-2026-2885/advisory.json",
 "markdown_url": "https://wpsec.com/vuln/WPSEC-2026-2885/index.md",
 "title": "Simply Schedule Appointments <= 1.6.13.0 - Unauthenticated Availability Check Bypass via 'start_date' Parameter",
 "description": "The Simply Schedule Appointments plugin for WordPress is vulnerable to an availability check bypass via the 'start_date' parameter in all versions up to, and including, 1.6.13.0 due to improper validation of the date format when creating or updating appointments. A non-canonical value such as one with a ' +1 day' suffix is parsed by PHP as a different moment than the date MySQL stores. This makes it possible for unauthenticated attackers to create appointments in slots that are already booked or otherwise unavailable, resulting in double-bookings.",
 "plugin": {
  "slug": "simply-schedule-appointments",
  "name": "Simply Schedule Appointments",
  "full_name": "Simply Schedule Appointments",
  "wordpress_org": "https://wordpress.org/plugins/simply-schedule-appointments/",
  "advisories_url": "https://wpsec.com/vuln/plugin/simply-schedule-appointments/",
  "attacksurface": "https://attacksurface.wpsec.com/plugin/simply-schedule-appointments"
 },
 "type": "BYPASS",
 "cwe": [
  "CWE-20"
 ],
 "cve": [],
 "cvss": {
  "version": "3.1",
  "score": 5.3,
  "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
  "severity": "Medium"
 },
 "affected": {
  "ranges": [
   {
    "from": null,
    "from_inclusive": true,
    "to": "1.6.13.4",
    "to_inclusive": false
   }
  ],
  "text": [
   "all versions before 1.6.13.4"
  ]
 },
 "introduced_in": null,
 "fixed_in": "1.6.13.4",
 "remediation": "Update to 1.6.13.4 or later.",
 "fix_released": "2026-11-10T20:33:39+00:00",
 "published": "2026-11-12T17:52:14+00:00",
 "updated": "2026-11-12T17:08:18.401852+00:00",
 "also_published_as": null,
 "references": [
  "https://wpsec.com/vuln/WPSEC-2026-2885/",
  "https://plugins.svn.wordpress.org/simply-schedule-appointments/tags/1.6.13.4/",
  "https://wordpress.org/plugins/simply-schedule-appointments/"
 ],
 "attacksurface_url": "https://attacksurface.wpsec.com/plugin/simply-schedule-appointments",
 "source": "WPSec",
 "license": {
  "name": "CC BY 4.0",
  "url": "https://creativecommons.org/licenses/by/4.0/"
 },
 "usage": {
  "plugin": "Medium",
  "affected_versions": "Medium",
  "as_of": "2026-11-12"
 }
}