Easy!Appointments disable_booking_message rendered as raw HTML on public booking page — Stored XSS

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

2.6 · CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:C/C:N/I:L/A:N

EPSS

• CVE-2026-52838: 0.22% estimated exploitation activity in the next 30 days; percentile 12.97 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Easy!Appointments allows administrators to define a custom "booking disabled" message through the booking settings page. That value is stored in the disablebookingmessage setting via a rich-text editor and later passed directly to the public bookingmessage view without escaping or sanitization: An authenticated administrator can store HTML or JavaScript in this field, enable disabled-booking mode, and trigger stored XSS in every unauthenticated visitor who opens the public booking page. --- Root Cause — Step by Step Code Flow Step 1 — Rich text editor value stored without sanitization The booking settings page collects the message value from the Trumbowyg rich-text editor and submits it as raw HTML: Step 2 — Settings controller saves value verbatim The backend settings controller persists the submitted value without any HTML sanitization: Step 3 — Public booking controller forwards stored value to view When booking is disabled, the public booking controller loads the stored…

Published by the source

29 Jul 2026, 16:30 UTC

Last modified by the source

29 Jul 2026, 16:45 UTC

Source last checked

26 Oct 2026, 14:50 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-996f-334j-67g7

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-996f-334j-67g7

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# Patch Next advisory brief: CVE-2026-52838

Advisory: Easy!Appointments disable_booking_message rendered as raw HTML on public booking page — Stored XSS
IDs: CVE-2026-52838, GHSA-996f-334j-67g7
Record: https://patchnext.com/advisories/cve-2026-52838 (revision 2, source checked 26 Oct 2026, 14:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 2.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist alextselegidis/easyappointments: affected <= 1.5.2

## Suggested inspection (read-only)
- Packagist alextselegidis/easyappointments: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on alextselegidis/easyappointments.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-996f-334j-67g7 (OSV record GHSA-996f-334j-67g7 lists affected ranges: Packagist alextselegidis/easyappointments >=0 <=1.5.2)
- Verified: https://github.com/advisories/GHSA-996f-334j-67g7 (GitHub-reviewed advisory GHSA-996f-334j-67g7 lists affected ranges: Packagist alextselegidis/easyappointments >=0 <=1.5.2)

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