# CVE-2026-18496: Booking Calendar <= 11.4.3 - Unauthenticated Sensitive Information Exposure in 'WPBC_FLEXTIMELINE_NAV' AJAX Action

> Unauthenticated attackers can extract sensitive customer data like names and emails via an AJAX action in the Booking Calendar plugin.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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:** 10 Oct 2026
- **Updated:** 11 Oct 2026
- **Also known as:** GHSA-865w-3pc6-gq4c

## What is CVE-2026-18496?

CVE-2026-18496 is a medium-severity vulnerability in wpdevelop Booking Calendar, published on 10 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Booking Calendar plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 11.4.3 via the wpbc_is_show_popover_in_flex_timeline() function. This makes it possible for unauthenticated attackers to extract sensitive data including names, email addresses, and phone numbers of customers who have made bookings.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2026-18496?


## How do I fix CVE-2026-18496?

No fix has been published for CVE-2026-18496 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-18496 being exploited?

There is no known exploitation of CVE-2026-18496 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18496 and fix it if it is affected.

What it is: CVE-2026-18496 is a medium-severity vulnerability in wpdevelop Booking Calendar, published on 10 Oct 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-2026-18496 in the wild and no public exploit code.

Affected product: wpdevelop Booking Calendar. 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-2026-18496/ (Markdown: https://insights.sbomify.com/CVE-2026-18496/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18496
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18496
- OSV: https://osv.dev/vulnerability/CVE-2026-18496

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18496/
Summaries are generated and may contain mistakes; the official description above is the record.