Vulnerability · Published May 22, 2026 · Assigned by Go
CVE-2026-42506Invoking incorrect handling of namespaced elements in foreign content in golang.org/x/net/html
Medium 6.1
In plain English
A medium-severity security flaw in golang.org/x/net/html from golang.org/x/net. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)6.1Medium
Exploit odds (30 days)0.2%top 85.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | golang-golang-x-net | no fix listed | DEBIAN-CVE-2026-42506 |
| Debian:13 | golang-golang-x-net | no fix listed | DEBIAN-CVE-2026-42506 |
| Debian:14 | golang-golang-x-net | 1:0.55.0-1 | DEBIAN-CVE-2026-42506 |
| Go | golang.org/x/net | 0.55.0 | GO-2026-5025 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| golang.org/x/net | golang.org/x/net/html | 0 – before 0.55.0 |