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GHSA-rmm7-r7wr-xpfg

CriticalCVSS 9 / 10
Published Jan 14, 2025·Last modified Jan 14, 2025
Affected Components(0)

No affected components available

Description

Impact

NOTE: The Realtime WYSIWYG Editor extension was experimental, and thus not recommended, in the versions affected by this vulnerability. It has become enabled by default, and thus recommended, starting with XWiki 16.9.0.

A user with only edit right can join a realtime editing session where others, that where already there or that may join later, have script or programming access rights. This user can then insert script rendering macros that are executed for those users in the realtime session that have script or programming rights. The inserted scripts can be used to gain more access rights.

Here's an example that works with XWiki 15.10.9+ and 16.2.0+:

  • the attacker starts editing a wiki page in realtime (for which they have edit right)
  • another user, with script or programming access right joins the editing session (e.g. by clicking on a link / URL provided by the attacker)
  • the attacker inserts a script rendering macro, say {{velocity}}I can run scripts{{/velocity}}, in the edited content, using the WYSIWYG editor UI
  • the edited content is reloaded for both the attacker and the other user, in order to render the inserted macro
    • the attacker gets a rendering error message
    • the other user sees "I can run scripts"

The attacker can obviously use more advanced scripts to gain access rights.

Before XWiki 15.10.9 and 16.2.0 the edited content was not re-rendered for all the users in the editing sesesion, but only for the user that inserted the macro. This means that in order to reproduce the problem the other user had to insert or update a macro or save and view the content.

Patches

This vulnerability has been patched in XWiki 15.10.12, 16.4.1 and 16.6.0-rc-1.

Workarounds

To avoid this vulnerability you can:

References

  • https://jira.xwiki.org/browse/XWIKI-21949

For more information

If you have any questions or comments about this advisory:

Risk Scores
Base Score
9.0

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.

Threat Intelligence
8.2

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
0.40%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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Critical severity
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