How severe is GHSA-w3wh-g4m9-783p?

GHSA-w3wh-g4m9-783p has a CVSS score of 9/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by GHSA-w3wh-g4m9-783p?

GHSA-w3wh-g4m9-783p affects the following packages: org.xwiki.rendering:xwiki-rendering-syntax-xhtml (Maven). Ecosystems affected: Maven.

How do I fix GHSA-w3wh-g4m9-783p?

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.

How do I detect GHSA-w3wh-g4m9-783p in my Maven dependencies?

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.

How do I mitigate GHSA-w3wh-g4m9-783p if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is GHSA-w3wh-g4m9-783p actively exploited in the wild?

No public exploit code has been indexed for GHSA-w3wh-g4m9-783p yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-w3wh-g4m9-783p?

GHSA-w3wh-g4m9-783p has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 35th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-w3wh-g4m9-783p?

GHSA-w3wh-g4m9-783p is classified as Cross-site Scripting (XSS) (CWE-79), CWE-80 (CWE-80). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was GHSA-w3wh-g4m9-783p published, and has it been updated?

GHSA-w3wh-g4m9-783p was published on July 14, 2025 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

CRITICAL severity

XWiki Rendering is vulnerable to XSS attacks through insecure XHTML syntaxGHSA-w3wh-g4m9-783p

CRITICALFix: xwiki/xwiki-rendering@a4ca31f

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.

Also known asCVE-2025-53835

Published

Jul 14, 2025

Updated

Sep 10, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs35th percentile — riskier than 35% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

☕org.xwiki.rendering:xwiki-rendering-syntax-xhtml

Real-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="&lt;script&gt;alert(1);&lt;/script&gt;"></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

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

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.xwiki.rendering:xwiki-rendering-syntax-xhtml`	≥ 5.4.5&&< 14.10	14.10`org.xwiki.rendering:xwiki-rendering-syntax-xhtml:14.10`

Affected Products

1 product · 1 configurations

Application

xwikixwiki

≥ 5.4.5 && < 14.10

range

Detection & mitigation playbook

Open-source dependency

Detect
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
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

### 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><