# CVE-2026-9357: vBulletin 6.x cross-site scripting in Login component

Source: https://junglewise.ai/threats/cve-2026-9357-vbulletin-6-x-cross-site-scripting-in-login-component  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-24. Updated: 2026-05-26  
License: CC BY 4.0 with a link back

CVE-2026-9357 · Severity: low · CVSS 3.5 · Published 2026-05-24

vBulletin, a widely used community forum software, contains a security vulnerability in its login component. An attacker can use this flaw to perform cross-site scripting (XSS) attacks, which could allow them to execute malicious scripts in the browser of other users. This could lead to unauthorized actions being performed on behalf of users or the theft of session information.

Technologies: [Vbulletin](https://junglewise.ai/threats/technologies/vbulletin). Vendors: [Vbulletin](https://junglewise.ai/threats/vendors/vbulletin).

## Quick answers

**Is CVE-2026-9357 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-9357 being exploited in the wild.

**How severe is CVE-2026-9357?** Low severity, with a CVSS score of 3.5, published 24 May 2026.

**Which products and versions are affected?** Vbulletin 6.x.

**Is there a fix for CVE-2026-9357?** 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-2026-9357 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-9357?** Check whether you run Vbulletin 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

A cross-site scripting (XSS) vulnerability exists in the Login component of vBulletin 6.x. The flaw stems from improper neutralization of user-supplied input during web page generation (CWE-79), which can also lead to code injection (CWE-94). An attacker with low-level privileges can exploit this remotely by manipulating login-related functions, though user interaction is required for the script to execute in the victim's browser. While a public exploit exists, the vendor has reportedly not responded to disclosure attempts, and no official patch is currently confirmed.

## Affected products

- vBulletin vBulletin 6.x

## Timeline

- 2026-05-24: disclosed: Public disclosure via VulDB and NVD
- 2026-05-24: advisory

## References

- [https://vuldb.com/submit/813052](https://vuldb.com/submit/813052)
- [https://vuldb.com/vuln/365320](https://vuldb.com/vuln/365320)
- [https://vuldb.com/vuln/365320/cti](https://vuldb.com/vuln/365320/cti)

## Related threats

- [vBulletin eval injection in vB5_Template_Runtime::runMaths](https://junglewise.ai/threats/cve-2026-61511-vbulletin-eval-injection-in-vb5-template-runtime-runmaths)
- [vBulletin denial of service via buddy list resource exhaustion](https://junglewise.ai/threats/cve-2025-46171-vbulletin-denial-of-service-via-buddy-list-resource-exhaustion)
- [vBulletin PHP Module Remote Code Execution Vulnerability](https://junglewise.ai/threats/cve-2019-16759-vbulletin-php-module-remote-code-execution-vulnerability)
- [vBulletin PHP Module Remote Code Execution Vulnerability](https://junglewise.ai/threats/cve-2020-17496-vbulletin-php-module-remote-code-execution-vulnerability)