# CVE-2026-11854: WSO2 authentication endpoint XSS via reflected error message

Source: https://junglewise.ai/threats/cve-2026-11854-the-authentication-endpoint-generates-an-error-message-that  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-28. Updated: 2026-10-28  
License: CC BY 4.0 with a link back

CVE-2026-11854 · Severity: medium · CVSS 6.1 · Published 2026-10-28

An authentication endpoint in a WSO2 product generates error messages that reflect user input without proper sanitization, allowing attackers to inject malicious scripts. An attacker could trick users into clicking a link that performs actions in their browser—such as redirecting them to a phishing site or altering the login page—but cannot steal session cookies due to security protections.

Vendors: [Wso2](https://junglewise.ai/threats/vendors/wso2).

## Quick answers

**Is CVE-2026-11854 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-11854 being exploited in the wild.

**How severe is CVE-2026-11854?** Medium severity, with a CVSS score of 6.1, published 28 October 2026.

**Which products and versions are affected?** Wso2 <UNKNOWN> <UNKNOWN>.

**Is there a fix for CVE-2026-11854?** 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-2026-11854 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-11854?** Check whether you run Wso2 <UNKNOWN> 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 reflected cross-site scripting (XSS) vulnerability exists in the authentication endpoint where unsanitized request data is included in error messages returned to the client. An unauthenticated attacker can craft a malicious URL containing JavaScript payloads that will execute in a victim's browser when the error page is rendered. Exploitation requires user interaction (clicking a link) but session hijacking is prevented by the httpOnly flag on session cookies.

## Affected products

- WSO2 <UNKNOWN> <UNKNOWN>

## Timeline

- 2026-10-28: disclosed

## References

- [https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2025-4850/](https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2025-4850/)

## Related threats

- [WSO2 product improper access control in resource location handling](https://junglewise.ai/threats/cve-2025-14260-due-to-the-improper-implementation-of-access-control-rules-the)