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GHSA-8g2j-rhfh-hq3r
No affected components available
Impact
The Markdown syntax is vulnerable to XSS through HTML. In particular, using Markdown syntax, it's possible for any user to embed Javascript code that will then be executed on the browser of any other user visiting either the document or the comment that contains it. In the instance that this code is executed by a user with admins or programming rights, this issue compromises the confidentiality, integrity and availability of the whole XWiki installation.
To reproduce, on an instance where the CommonMark Markdown Syntax 1.2 extension is installed, log in as a user without script rights. Edit a document and set its syntax to Markdown. Then , add the content <script>alert("XSS")</script> and refresh the page. If an alert appears containing "XSS", then the instance is vulnerable.
Patches
This has been patched in version 8.9 of the CommonMark Markdown Syntax 1.2 extension.
Workarounds
We're not aware of any workaround except upgrading.
References
- https://jira.xwiki.org/browse/MARKDOWN-80
- https://github.com/xwiki-contrib/syntax-markdown/commit/d136472d6e8a47981a0ede420a9096f88ffa5035
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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