Cross-site scripting in Go programming language - CVE-2026-56858
Published: August 18, 2026
Vulnerability identifier: #VU144177
CSH Severity: Medium
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N]
CVE-ID: CVE-2026-56858
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to inject arbitrary content, potentially leading to cross-site scripting.
The vulnerability exists due to improper neutralization of special elements in html/template when rendering pathological inputs that close an unescaped '/' early. A remote attacker can supply crafted input data to inject arbitrary content, potentially leading to cross-site scripting.
Affected software
Go programming language
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
golang (Red Hat package)
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
golang (Red Hat package)
How to mitigate CVE-2026-56858
Install security update from vendor's website.
Go programming language - addressed in versions 1.25.13, 1.26.6, 1.27.0 rc.3
golang (Red Hat package) - addressed in versions 1.26.7-1.el9_8, 1.26.7-1.el10_2
golang (Red Hat package) - addressed in versions 1.26.7-1.el9_8, 1.26.7-1.el10_2