CVE-2026-11854: XSS (CVSS 6.1)

Description

The authentication endpoint generates an error message that includes reflected data directly from the request without sufficient sanitization or encoding. This allows an attacker to inject malicious scripts that can be executed in the context of a victim's browser. Successful exploitation enables an attacker to perform actions within the user's browser, such as redirecting the user to a malicious website, modifying the web page's user interface, or retrieving information. However, due to the httpOnly flag on session-related cookies, session hijacking or similar attacks are not possible.

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CVSS v3.1 Score

6.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.12%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

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

Frequently Asked Questions

What is CVE-2026-11854? +

The authentication endpoint generates an error message that includes reflected data directly from the request without sufficient sanitization or encoding. This allows an attacker to inject malicious scripts that can be executed in the context of a victim's browser. Successful exploitation enables an attacker to perform actions within the user's browser, such as redirecting the user to a malicious website, modifying the web page's user interface, or retrieving information. However, due to the httpOnly flag on session-related cookies, session hijacking or similar attacks are not possible. It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2026-11854? +

CVE-2026-11854 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0021, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-11854? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-11854