The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 1.6.12.10 via the ssa_past_appointments due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with contributor-level access and above, to access appointment records belonging to arbitrary users and harvest the per-appointment ownership tokens (32-character hashes) embedded in the rendered HTML, which can then be used without any authentication to read or modify those appointments including full customer PII such as name, email, phone number, and private notes. The /wp-json/ssa/v1/render-shortcode REST endpoint is registered unconditionally on rest_api_init regardless of whether the Divi theme is installed, and its permission callback only requires current_user_can('edit_posts'), meaning any Contributor-level account is sufficient to trigger this entire exploit chain.
CVE-2026-13358
Score 6.5 from GitHub Security Advisory published 2026-08-16. a secondary CVSS source baseline 6.5; sources differ by 0.0.
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.5
- EG Score
- 6.5(high)
- EG Risk
- 29(Track)EG Risk 29/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity65% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 40%
- KEV
- Not listed
Published
August 16, 2026
Last Modified
August 20, 2026
References (12)
- security@wordfencehttps://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/class-appointment-model.php#L1936
- security@wordfencehttps://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/class-db-model.php#L325
- security@wordfencehttps://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/class-divi.php#L237
- security@wordfencehttps://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/class-divi.php#L254
- security@wordfencehttps://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.11.0/includes/class-shortcodes.php#L781
- security@wordfencehttps://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.12.4/includes/class-appointment-model.php#L1936
- security@wordfencehttps://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.12.4/includes/class-db-model.php#L325
- security@wordfencehttps://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.12.4/includes/class-divi.php#L237
- security@wordfencehttps://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.12.4/includes/class-divi.php#L254
- security@wordfencehttps://plugins.trac.wordpress.org/browser/simply-schedule-appointments/tags/1.6.12.4/includes/class-shortcodes.php#L781
- security@wordfencehttps://plugins.trac.wordpress.org/changeset?reponame=&old=3617759%40simply-schedule-appointments&new=3617759%40simply-schedule-appointments
- security@wordfencehttps://www.wordfence.com/threat-intel/vulnerabilities/id/5dbe5094-d255-46b1-9e8e-9c48cd74e8a2?source=cve
Vendor Advisories for CVE-2026-13358(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 18× in last 7d / 18× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-08-20 22:55 UTCEPSS rescore
- 2026-08-20 13:00 UTCGHSA enrichment
- 2026-08-20 00:16 UTCEG score recompute
- 2026-08-20 00:16 UTCGHSA enrichment
- 2026-08-19 17:03 UTCEPSS rescore
- 2026-08-18 22:21 UTCEG score recompute
- 2026-08-18 22:21 UTCGHSA enrichment
- 2026-08-18 13:48 UTCEPSS rescore
- 2026-08-17 20:29 UTCEG score recompute
- 2026-08-17 20:29 UTCGHSA enrichment
- 2026-08-17 19:40 UTCEG score recompute
- 2026-08-17 19:40 UTCGHSA enrichment
- 2026-08-17 07:21 UTCEG score recompute
- 2026-08-17 07:21 UTCGHSA enrichment
- 2026-08-16 14:56 UTCEPSS rescore
- 2026-08-16 05:29 UTCEG score recompute
- 2026-08-16 04:41 UTCEG score recompute
- 2026-08-16 04:41 UTCMITRE cvelistV5first tracked
Frequently asked(5)
What is CVE-2026-13358?
When was CVE-2026-13358 disclosed?
Is CVE-2026-13358 actively exploited?
What is the CVSS score of CVE-2026-13358?
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Dependency Blast Radius
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