CVE-2026-56858

Fix Javascript regexp context tracking in html/template

State: Published
Severity: 6.1 Medium
Published: Aug 13, 2026
Updated: Aug 14, 2026
Reserved: Jun 23, 2026

Description

Previously, pathological inputs could close an unescaped '/' early, allowing for attack-controlled data to inject arbitrary content, potentially leading to XSS.

Scores

CVSS	Score	Vector	Source
3.1	6.1 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N	CISA-ADP

Weaknesses

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected Products

Product	Versions
html/templateGo standard library	before 1.25.13Affected 1.26.0-0 to before 1.26.6Affected 1.27.0-0 to before 1.27.0-rc.3Affected

References

https://go.dev/issue/80435
https://go.dev/cl/807100
https://groups.google.com/g/golang-announce/c/94pEornpRlI
https://pkg.go.dev/vuln/GO-2026-6091

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.