CVE-2026-39823

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

Published May 7, 2026 CVSS 3.1 · 6.1 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Golang
Golang go
CPEs cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*
Vendors & Products Golang
Golang go
Type Values Removed Values Added
Weaknesses CWE-79
Type Values Removed Values Added
Weaknesses CWE-79
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Go Standard Library
Go Standard Library html/template
Vendors & Products Go Standard Library
Go Standard Library html/template
Type Values Removed Values Added
Weaknesses CWE-79
Type Values Removed Values Added
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.
Title Bypass of meta content URL escaping causes XSS in html/template
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Go
Published
Updated
May 8, 2026, 2:05 PM
Reserved
Apr 7, 2026, 6:13 PM
Status
Analyzed
Published
May 7, 2026, 8:16 PM
Modified
Oct 26, 2026, 8:10 PM