CVE-2026-27136

Invoking duplicate attributes can cause XSS in golang.org/x/net/html

Description

Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.

Patch Available

Fix available through Seal Security. No upgrade required, protect your application instantly.

Fix without upgrading

Score

6.1

Severity

Medium

Ecosystem

Publish Date

May 21, 2026

Modified Date

May 30, 2026

Score Vector

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

Affected Versions