CVE-2026-39823

MEDIUM

Bypass of meta content URL escaping causes XSS in html/template

Title source: cna

Description

CVE-2026-27142 fixed a vulnerability in which URLs were not correctly escaped inside of a <meta> tag's <content> attribute. If the URL content were to insert ASCII whitespaces around the '=' rune inside of the <content> attribute, the escaper would fail to similarly escape it, leading to XSS.

References (4)

Core 4

Core References

https://go.dev/issue/78913

https://go.dev/cl/769920

https://groups.google.com/g/golang-announce/c/qcCIEXso47M

https://pkg.go.dev/vuln/GO-2026-4982

Scores

CVSS v3 6.1

EPSS 0.0001

EPSS Percentile 1.2%

Attack Vector NETWORK

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

CISA SSVC

Vulnrichment

Exploitation none

Automatable no

Technical Impact partial

Details

CWE

CWE-79

Status published

Products (3)

Go standard library/html/template < 1.25.10

Go standard library/html/template 1.26.0-0 - 1.26.3

golang/go < 1.25.10

Published May 07, 2026

Tracked Since May 08, 2026