# CVE-2026-91847: Bookly < 28.2 - Unauthenticated AI Assistant Conversation Disclosure and Message Injection via IDOR

> Unauthenticated attackers can read and inject messages into other users' AI booking assistant conversations due to missing ownership verification.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/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:** 19 Sep 2026
- **Updated:** 19 Sep 2026
- **Also known as:** GHSA-mj5r-8jcf-67xr

## What is CVE-2026-91847?

CVE-2026-91847 is a medium-severity missing authorization vulnerability in Unknown Online Scheduling and Appointment Booking System, published on 19 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Online Scheduling and Appointment Booking System  WordPress plugin before 28.2 does not verify that the requester owns the AI booking-assistant conversation named in its unauthenticated conversation actions, allowing any unauthenticated visitor to read another visitor's assistant messages and to inject messages into their in-progress conversation.

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

## Which versions are affected by CVE-2026-91847?


## How do I fix CVE-2026-91847?

No fix has been published for CVE-2026-91847 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-91847 being exploited?

There is no known exploitation of CVE-2026-91847 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-91847 and fix it if it is affected.

What it is: CVE-2026-91847 is a medium-severity missing authorization vulnerability in Unknown Online Scheduling and Appointment Booking System, published on 19 Sep 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-2026-91847 in the wild and no public exploit code.

Affected product: Unknown Online Scheduling and Appointment Booking System. 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-2026-91847/ (Markdown: https://insights.sbomify.com/CVE-2026-91847/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-91847
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-91847
- OSV: https://osv.dev/vulnerability/CVE-2026-91847

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-91847/
Summaries are generated and may contain mistakes; the official description above is the record.