GHSA-9xc6-c2rm-f27p
XWiki vulnerable to remote code execution through insufficient protection against {{/html}} injection
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
org.xwiki.rendering:xwiki-rendering-xml☕org.xwiki.rendering:xwiki-rendering-xml☕org.xwiki.rendering:xwiki-rendering-xmlReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Any user who can edit their own user profile or any other document can execute arbitrary script macros including Groovy and Python macros that allow remote code execution including unrestricted read and write access to all wiki contents. The reason is that rendering output is included as content of HTML macros with insufficient escaping, and it is thus possible to close the HTML macro and inject script macros that are executed with programming rights. To demonstrate, the content {{html}}{{/html {{/html}}}} can be inserted into any field of the user profile that supports wiki syntax like the "About" field. If this leads to the display of raw HTML, the instance is vulnerable.
Patches
This problem has been patched by extending the escaping introduced by XRENDERING-693 to also cover closing HTML macros that have spaces after the macro name in XWiki 16.10.10, 17.4.3 and 17.6.0RC1. A similar fix has been applied in org.xwiki.platform:xwiki-platform-oldcore as an extra safety net, see XWIKI-23378. At this point, we're not aware that this extra safety net would be required for security.
The patch also fixes the injection of opening HTML macro syntaxes, e.g., with {{html}}{{html{{/html}}}} which disrupts the rendering of the user profile but for which we haven't found any further security impact apart from the disruption of the UI.
Workarounds
We're not aware of any workarounds except for upgrading the affected module to a version with a fix.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.xwiki.rendering:xwiki-rendering-xml | all versions | 16.10.10 |
| ☕Maven | org.xwiki.rendering:xwiki-rendering-xml | ≥ 17.0.0-rc-1&&< 17.4.3 | 17.4.3 |
| ☕Maven | org.xwiki.rendering:xwiki-rendering-xml | ≥ 17.5.0-rc-1&&< 17.6.0-rc-1 | 17.6.0-rc-1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.xwiki.rendering:xwiki-rendering-xml. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.xwiki.rendering:xwiki-rendering-xml to 16.10.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9xc6-c2rm-f27p is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-9xc6-c2rm-f27p is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-9xc6-c2rm-f27p. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-9xc6-c2rm-f27p in your dependencies?
O3 detects GHSA-9xc6-c2rm-f27p across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.