# CVE-2026-39601: WordPress Booking Calendar plugin <= 11.8.4 - Race Condition vulnerability

> An attacker can exploit a race condition in the Booking Calendar plugin to manipulate shared resources, potentially altering booking data.

- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/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:** 2 Oct 2026
- **Updated:** 5 Oct 2026
- **Also known as:** GHSA-c83g-wfv6-9ghj

## What is CVE-2026-39601?

CVE-2026-39601 is a low-severity vulnerability in WPdevelop Booking Calendar, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in WPdevelop Booking Calendar booking allows Leveraging Race Conditions.This issue affects Booking Calendar: from n/a through 11.8.4.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-39601?


## How do I fix CVE-2026-39601?

No fix has been published for CVE-2026-39601 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-39601 being exploited?

There is no known exploitation of CVE-2026-39601 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-39601 and fix it if it is affected.

What it is: CVE-2026-39601 is a low-severity vulnerability in WPdevelop Booking Calendar, published on 2 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-2026-39601 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-2026-39601/ (Markdown: https://insights.sbomify.com/CVE-2026-39601/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-39601
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-39601
- OSV: https://osv.dev/vulnerability/CVE-2026-39601

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-39601/
Summaries are generated and may contain mistakes; the official description above is the record.