Golang Net vulnerabilities

CVE-2026-42506 Medium · 6.1 CWE-79 May 22, 2026

Invoking incorrect handling of namespaced elements in foreign content in golang.org/x/net/html

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.

CVE-2026-42502 Medium · 6.1 CWE-1021 May 22, 2026

Invoking incorrect handling of HTML elements in foreign content in golang.org/x/net/html

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.

CVE-2026-39821 Critical · 9.6 CWE-1289 May 22, 2026

Invoking failure to reject ASCII-only Punycode-encoded labels in golang.org/x/net/idna

The ToASCII and ToUnicode functions incorrectly accept Punycode-encoded labels that decode to an ASCII-only label. For example, ToUnicode("xn--example-.com") incorrectly returns the name "example.com" rather than an error. This behavior can lead to privilege escalation in programs using the idna package. For example, a program which performs privilege checks on the ASCII hostname may reject "example.com" but permit "xn--example-.com". If that program subsequently converts the ASCII hostname to Unicode, it will inadvertently permits access to the Unicode name "example.com".

CVE-2026-27136 Medium · 6.1 CWE-1021 May 22, 2026

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

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.

CVE-2026-25681 Medium · 6.1 CWE-1021 May 22, 2026

Invoking incorrect handling of character references in DOCTYPE nodes in golang.org/x/net/html

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.

CVE-2026-25680 Medium · 6.5 CWE-400 May 22, 2026

Invoking denial of service when parsing arbitrary HTML in golang.org/x/net/html

Parsing arbitrary HTML can consume excessive CPU time, possibly leading to denial of service.