CVE-2026-39823

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

MEDIUM 6.1

At a glance

Source: NVD
EPSS: EPSS 0.31 % · percentile 24 (2026-10-28)
State: PUBLISHED
Published: 2026-05-07 19:41 UTC
Updated: 2026-05-08 14:05 UTC
Assigner: Go
NVD status: Analyzed

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.

Weaknesses (CWE)

CWE-79 — Cross-site Scripting (XSS)

References

Scores

Version	Score	Vector	Scored by
CVSS 3.1	MEDIUM 6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N	CISA-ADP
CVSS 3.1	MEDIUM 6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N	NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

Advisories

GO-2026-4982 — Bypass of meta content URL escaping causes XSS in html/template

European references

ENISA EUVD · EUVD-2026-28424
GCVE · GCVE-0-2026-39823

CERT-FR advisories

CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
CERTFR-2026-AVI-1281 — Multiples vulnérabilités dans les produits Splunk · cert.ssi.gouv.fr
CERTFR-2026-AVI-1249 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:a:golang:go:*:*:*:*:*:*:*:* < 1.25.10
cpe:2.3:a:golang:go:*:*:*:*:*:*:*:* ≥ 1.26.0 < 1.26.3

Affected products

Product	Versions
Go standard library · html/template	affected 0 < 1.25.10 ; affected 1.26.0-0 < 1.26.3

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD