GHSA-w3wh-g4m9-783p is a critical-severity (CVSS 9) Cross-site Scripting (XSS) vulnerability in org.xwiki.rendering:xwiki-rendering-syntax-xhtml. A fix is available for org.xwiki.rendering:xwiki-rendering-syntax-xhtml — see the affected versions and patch details below.
XWiki Rendering is vulnerable to XSS attacks through insecure XHTML syntax
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-w3wh-g4m9-783p.
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.
How urgent is this, really
GHSA-w3wh-g4m9-783p plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
org.xwiki.rendering:xwiki-rendering-syntax-xhtmlReal-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
The XHTML syntax depended on the xdom+xml/current syntax which allows the creation of raw blocks that permit the insertion of arbitrary HTML content including JavaScript. This allows XSS attacks for users who can edit a document like their user profile (enabled by default). The attack works by setting the document's syntax to xdom+xml/current and then inserting content like
<document><p><metadata><metadata><entry><string>syntax</string><org.xwiki.rendering.syntax.Syntax><type><name>XHTML</name><id>xhtml</id><variants class="empty-list"></variants></type><version>5</version></org.xwiki.rendering.syntax.Syntax></entry></metadata></metadata></p><rawtext syntax="html/5.0" content="<script>alert(1);</script>"></rawtext></document>
This has been fixed by removing the dependency on the xdom+xml/current syntax from the XHTML syntax. Note that the xdom+xml syntax is still vulnerable to this attack. As it's main purpose is testing and its use is quite difficult, this syntax shouldn't be installed or used on a regular wiki. We're currently not aware of any further dependencies on it.
Patches
The fix of removing the dependency has been included in XWiki 14.10. It is not released for earlier versions due to the potential breakages, among others this change makes it necessary to update the Confluence XHTML syntax as it relies on internals that were changed for the fix. Similar XSS fixes were also not applied to the LTS version 13.10.x due to the potential breakages.
Workarounds
There are no known workarounds apart from upgrading.
References
- https://jira.xwiki.org/browse/XRENDERING-660
- https://github.com/xwiki/xwiki-rendering/commit/a4ca31f99f524b9456c64150d6f375984aa81ea7
For more information
If you have any questions or comments about this advisory:
- Open an issue in Jira XWiki.org
- Email us at Security Mailing List
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.xwiki.rendering:xwiki-rendering-syntax-xhtml | ≥ 5.4.5&&< 14.10 | 14.10org.xwiki.rendering:xwiki-rendering-syntax-xhtml:14.10 |
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-syntax-xhtml, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.xwiki.rendering:xwiki-rendering-syntax-xhtml to 14.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w3wh-g4m9-783p 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-w3wh-g4m9-783p can be triaged on real exposure rather than presence alone.
Tailored to GHSA-w3wh-g4m9-783p. 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-w3wh-g4m9-783p in your dependencies?
O3 Security finds GHSA-w3wh-g4m9-783p across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.