Answer in brief
CVE-2026-91109 records a Medium severity (CVSS 6.5) vulnerability in Simply Schedule Appointments <= 1.6.12.31 - Insecure Direct Object Reference to Authenticated (Subscriber+) Sensitive Information Disclosure via 'complete_group' Parameter. The current sources do not mark it as known exploited. The current feed maps croixhaug/Simply Schedule Appointments (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps croixhaug/Simply Schedule Appointments (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| croixhaug/Simply Schedule Appointmentsgeneric | >=0 <=1.6.12.31 | Not reported |
Published upstream
Oct 1, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 1, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 1, 2026
The Simply Schedule Appointments plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 1.6.12.31 via the 'complete_group' parameter due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with subscriber-level access and above, to disclose every co-booker's private per-appointment id_token (exposed as public_token) alongside their PII (name and email address), then use each leaked token to read, overwrite arbitrary appointment meta on, or cancel the co-booker's appointment via the same REST controller. Exploitation requires the attacker to possess a valid id_token for any single appointment within the targeted group booking.
Quoted source text, attributed separately from HOL analysis.