CVE-2026-1708 | Appointment Booking Calendar <= 1.6.9.27 - Unauthenticated SQL Injection via 'append_where_sql' Parameter

The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to blind SQL Injection in all versions up to, and including, 1.6.9.27. This is due to the `db_where_conditions` method in the `TD_DB_Model` class failing to prevent the `append_where_sql` parameter from being passed through JSON request bodies, while only checking for its presence in the `$_REQUEST` superglobal. This makes it possible for unauthenticated attackers to append arbitrary SQL commands to queries and extract sensitive information from the database via the `append_where_sql` parameter in JSON payloads granted they have obtained a valid `public_token` that is inadvertently exposed during the booking flow.

Published: 2026-03-11 Last update: 2026-04-22 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-1708 is rated Moderate Risk (42.8/100): CVSS High severity, with low exploitation likelihood (EPSS 0.16%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-1708

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-17 0.12% 0.16% +0.04%
2 2026-03-11 0.12%

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-1708

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-1708

Affected software / configurations for CVE-2026-1708

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-1708

URL Tags
https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.21/includes/class-appointment-model.php#L1340
https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.21/includes/class-appointment-model.php#L1413
https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.21/includes/lib/td-util/class-td-db-model.php#L1019
https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.9.21/includes/lib/td-util/class-td-db-model.php#L1025
https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/trunk/includes/class-appointment-model.php#L1340
https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/trunk/includes/class-appointment-model.php#L1413
https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/trunk/includes/lib/td-util/class-td-db-model.php#L1019
https://plugins.trac.wordpress.org/browser/simply-schedule-appointments/trunk/includes/lib/td-util/class-td-db-model.php#L1025
https://plugins.trac.wordpress.org/changeset/3475885/simply-schedule-appointments/trunk/includes/lib/td-util/class-td-db-model.php
https://www.wordfence.com/threat-intel/vulnerabilities/id/71642341-9fe0-44a9-88f3-70167dc6ca62?source=cve
cvelogic Threat Intelligence