CVE-2026-42506

A flaw was found in golang.org/x/net/html. When parsing arbitrary HTML that is subsequently rendered, an unexpected HTML tree can be generated. A remote attacker could leverage this vulnerability to execute Cross-Site Scripting (XSS) attacks in applications that attempt to sanitize input HTML before rendering, potentially leading to unauthorized actions or information disclosure.

This Moderate flaw in golang.org/x/net/html can lead to Cross-Site Scripting (XSS) in applications that process and render untrusted HTML, even when input sanitization is implemented. The vulnerability arises from an unexpected HTML tree structure generated during parsing, potentially allowing a remote attacker to execute arbitrary script code in the user's browser, leading to information disclosure or unauthorized actions.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Update affected Go applications to use golang.org/x/net version 0.55.0 or later. As a workaround, do not use golang.org/x/net/html to parse and re-render untrusted HTML content. Applications that do not parse arbitrary HTML are not affected.