# CVE-2026-13358: Information disclosure in Simply Schedule Appointments

> Authenticated contributors can access arbitrary appointment records and tokens, enabling unauthorized reading and modification of customer PII.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** GHSA-w9gm-5x7r-8v42

## What is CVE-2026-13358?

CVE-2026-13358 is a medium-severity vulnerability in croixhaug Simply Schedule Appointments, published on 16 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-13358?


## How do I fix CVE-2026-13358?

No fix has been published for CVE-2026-13358 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-13358 being exploited?

There is no known exploitation of CVE-2026-13358 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-13358 and fix it if it is affected.

What it is: CVE-2026-13358 is a medium-severity vulnerability in croixhaug Simply Schedule Appointments, published on 16 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-13358 in the wild and no public exploit code.

Affected product: croixhaug Simply Schedule Appointments. 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-2026-13358/ (Markdown: https://insights.sbomify.com/CVE-2026-13358/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-13358
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-13358
- OSV: https://osv.dev/vulnerability/CVE-2026-13358

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-13358/
Summaries are generated and may contain mistakes; the official description above is the record.