CVE-2021-21383 XSS in Wiki.js

High 7.6 Published 18 Mar 2021 Updated 3 Aug 2024

A malicious user can inject JavaScript into Wiki.js pages via mustache expressions in code blocks, leading to stored XSS when viewed by others.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2021-21383?

CVE-2021-21383 is a high-severity cross-site scripting vulnerability in Requarks wiki, published on 18 Mar 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

Official description

Wiki.js an open-source wiki app built on Node.js. Wiki.js before version 2.5.191 is vulnerable to stored cross-site scripting through mustache expressions in code blocks. This vulnerability exists due to mustache expressions being parsed by Vue during content injection even though it is contained within a `<pre>` element. By creating a crafted wiki page, a malicious Wiki.js user may stage a stored cross-site scripting attack. This allows the attacker to execute malicious JavaScript when the page is viewed by other users. For an example see referenced GitHub Security Advisory. Commit 5ffa189383dd716f12b56b8cae2ba0d075996cf1 fixes this vulnerability by adding the v-pre directive to all `<pre>` tags during the render.

Weakness: CWE-79

Which versions are affected by CVE-2021-21383?

It affects 1 product.

Products include Requarks Wiki.js.

How do I fix CVE-2021-21383?

No fix has been published for CVE-2021-21383 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2021-21383 being exploited?

There is no known exploitation of CVE-2021-21383 in the wild and no public exploit code.

Sources

Also known as GHSA-6xx4-m8gx-826r.