# CVE-2026-6937: Missing authorization in Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin

> Unauthenticated attackers can modify arbitrary appointment records and expose customer PII via the bulk appointments REST API endpoint due to missing authorization checks.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 May 2026
- **Updated:** 28 May 2026
- **Also known as:** GHSA-4cp9-7xpg-wmvc

## What is CVE-2026-6937?

CVE-2026-6937 is a medium-severity missing authorization vulnerability in croixhaug Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin, published on 28 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-6937?


## How do I fix CVE-2026-6937?

No fix has been published for CVE-2026-6937 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-6937 being exploited?

There is no known exploitation of CVE-2026-6937 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6937 and fix it if it is affected.

What it is: CVE-2026-6937 is a medium-severity missing authorization vulnerability in croixhaug Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin, published on 28 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-6937 in the wild and no public exploit code.

Affected product: croixhaug Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-6937/ (Markdown: https://insights.sbomify.com/CVE-2026-6937/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6937
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6937
- OSV: https://osv.dev/vulnerability/CVE-2026-6937

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-6937/
Summaries are generated and may contain mistakes; the official description above is the record.