Vulnerability identifier: #VU80572

Vulnerability risk: Medium

CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2023-39318

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Go programming language
Universal components / Libraries / Scripting languages

Vendor: Google

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data within the html/template package when handling HMTL-like "<!--" and "-->" comment tokens, nor hashbang "#!" comment tokens, in <script> contexts. A remote attacker can pass specially crafted input to the application and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Go programming language: 1.21 rc1 - 1.21.0, 1.20 - 1.20.7

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External links
http://groups.google.com/g/golang-announce/c/Fm51GRLNRvM/m/F5bwBlXMAQAJ?pli=1
http://go.dev/issue/62196

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.