What is CVE-2026-42506?

CVE-2026-42506 is a medium-severity vulnerability in Golang Net, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-05-22.

How severe is CVE-2026-42506?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Golang Net

CVE-2026-42506

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.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-05-22 · last modified 2026-07-23.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (24.9th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 24.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

Golang Net
Golang.org/x/net Golang.org/x/net/html — versions 0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

go.dev/issue/79571 (Issue Tracking)
groups.google.com/g/golang-announce/c/iI-mYSI0lu8 (Mailing List)
go.dev/cl/781700 (Issue Tracking)
pkg.go.dev/vuln/GO-2026-5025 (Vendor Advisory)

Frequently asked questions

What is CVE-2026-42506?: CVE-2026-42506 is a medium-severity vulnerability in Golang Net, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-05-22.
How severe is CVE-2026-42506?: Medium severity. CVSS v3 base score is 6.1 out of 10.