What is the CVSS score of CVE-2026-6937?

CVE-2026-6937 has a CVSS 3.1 base score of 5.3 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N. EPSS exploitation probability: 0.2%.

Simply Schedule Appointments CVE-2026-6937

EUVD-2026-32747 MEDIUM

Missing Authorization (CWE-862)

2026-05-28 Wordfence

GHSA-4cp9-7xpg-wmvc

WordPress Authentication Bypass Appointment Booking Calendar Simply Schedule Appointments Booking Plugin Wordpress Plugin Croixhaug

5.3

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

5.3 MEDIUM

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Lifecycle Timeline

Analysis Generated

May 28, 2026 - 09:23 vuln.today

CVE Published

May 28, 2026 - 07:43 nvd

MEDIUM 5.3

DescriptionCVE.org

The Appointment Booking Calendar - Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 1.6.11.8 due to the plugin not properly verifying that a user is authorized to perform an action via the bulk appointments REST API endpoint. This makes it possible for unauthenticated attackers to modify arbitrary appointment records including customer PII, payment status, and meeting URL fields, and to expose full customer PII from existing appointment records via the bulk endpoint response. The public nonce is a static, user-independent value present in the HTML source of any page hosting the [ssa_booking] shortcode, meaning any visitor who has viewed such a page can obtain it and target any appointment in the system without authentication.

AnalysisAI

Missing authorization on the bulk appointments REST API endpoint in Simply Schedule Appointments WordPress plugin (all versions up to and including 1.6.11.8) permits unauthenticated mass modification and disclosure of customer appointment data. The flaw is compounded by a static, user-independent nonce embedded in the HTML source of any page rendering the [ssa_booking] shortcode, meaning a single anonymous page visit yields a credential sufficient to target every appointment in the system. An attacker can overwrite customer PII, alter payment status, and hijack meeting URLs across all bookings, or enumerate full customer records via the bulk endpoint response - no account or session required. No public exploit code and no CISA KEV listing are identified at time of analysis.

Technical ContextAI

The Simply Schedule Appointments plugin (CPE: cpe:2.3:a:croixhaug:appointment_booking_calendar_-_simply_schedule_appointments_booking_plugin:*:*:*:*:*:*:*:*) registers a bulk appointments REST API endpoint in class-bootstrap.php (line 151). Authorization for this endpoint relies solely on nonce verification rather than WordPress capability checks. CWE-862 (Missing Authorization) describes this root cause: the system validates that a request carries a recognized nonce token but never confirms that the requesting user has the privilege to perform the bulk operation. The critical aggravating factor is that the nonce is generated as a static, user-independent value that is written into the HTML source of every page hosting the [ssa_booking] shortcode. The API model logic at class-td-api-model.php (line 74) and appointment record operations at class-appointment-model.php (line 724) are referenced in Wordfence's disclosure and the WordPress plugin trac source, confirming the specific code paths involved. Any anonymous visitor who renders a booking page obtains this nonce and can immediately direct it at the bulk endpoint against any appointment ID in the database.

RemediationAI

An upstream fix is referenced via WordPress plugin trac changeset 3549843 (https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3549843%40simply-schedule-appointments&new=3549843%40simply-schedule-appointments), indicating the vendor has committed a patch; however, the exact released version number beyond 1.6.11.8 that includes this fix is not independently confirmed from the available data - verify the latest available version via the WordPress plugin dashboard or the Wordfence advisory before assuming a specific version is safe. Site administrators should update the Simply Schedule Appointments plugin to the latest available version immediately using WordPress Admin > Plugins > Update. As a compensating control where immediate patching is not possible, removing the [ssa_booking] shortcode from all publicly accessible pages prevents anonymous visitors from obtaining the static nonce, raising the exploitation barrier significantly - though this disables booking functionality for end users. A web application firewall rule blocking unauthenticated POST requests to the plugin's bulk REST API path (typically /wp-json/ssa/v1/appointments/bulk or similar) can also reduce exposure without affecting normal booking flows, though endpoint path should be confirmed against the specific plugin version in use.