# CVE-2026-36723: BookCars unrestricted file rename in /api/create-user component

Source: https://junglewise.ai/threats/cve-2026-36723-bookcars-unrestricted-file-rename-in-api-create-user-component  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-09. Updated: 2026-06-09  
License: CC BY 4.0 with a link back

CVE-2026-36723 · Severity: info · CVSS 9.8 · Published 2026-06-09

BookCars, a car rental management system, contains a security flaw in its user creation component. An authenticated user can exploit this to move and rename files on the server, potentially leading to a full system takeover. This could result in the theft of customer data, service disruption, or the installation of malicious software on the company's infrastructure.

Technologies: [BookCars](https://junglewise.ai/threats/technologies/bookcars). Vendors: [BookCars](https://junglewise.ai/threats/vendors/bookcars).

## Quick answers

**Is CVE-2026-36723 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-36723 being exploited in the wild.

**How severe is CVE-2026-36723?** Informational severity, with a CVSS score of 9.8, published 9 June 2026.

**Which products and versions are affected?** BookCars 8.3.

**Is there a fix for CVE-2026-36723?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-36723 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-36723?** Check whether you run BookCars at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An unrestricted file rename vulnerability exists in the /api/create-user endpoint of BookCars v8.3, specifically within the userRoutes.ts and userController.ts components. Authenticated attackers can utilize directory traversal sequences (e.g., ../) to move files from temporary storage to arbitrary locations on the server's filesystem. This flaw allows for the overwriting of critical application files or the placement of malicious scripts in web-accessible directories. Successful exploitation can lead to unauthorized access to sensitive data, persistent system compromise, and remote code execution (RCE).

## Affected products

- BookCars BookCars 8.3

## Timeline

- 2026-06-09: disclosed: Initial vulnerability disclosure and CVE assignment.
- 2026-06-09: advisory: NVD published the vulnerability details.

## References

- [https://github.com/CC-T-454455/Vulnerabilities/tree/master/bookcars/vulnerability-17](https://github.com/CC-T-454455/Vulnerabilities/tree/master/bookcars/vulnerability-17)

## Related threats

- [BookCars authentication bypass via forged JWT in social-sign-in](https://junglewise.ai/threats/cve-2026-36727-bookcars-authentication-bypass-via-forged-jwt-in-social-sign-in)
- [BookCars arbitrary file deletion via directory traversal in delete-temp-license](https://junglewise.ai/threats/cve-2026-36726-bookcars-arbitrary-file-deletion-via-directory-traversal-in)
- [BookCars arbitrary file upload in create-license and create-car-image API](https://junglewise.ai/threats/cve-2026-36722-bookcars-arbitrary-file-upload-in-create-license-and-create-car)
- [bookcars authentication bypass via forged JWT in validateAccessToken](https://junglewise.ai/threats/cve-2026-36721-bookcars-authentication-bypass-via-forged-jwt-in)
- [BookCars privilege escalation in update-user endpoint](https://junglewise.ai/threats/cve-2026-36720-bookcars-privilege-escalation-in-update-user-endpoint)