CVE-2023-37908 is a critical-severity (CVSS 9) CWE-83 vulnerability in org.xwiki.rendering:xwiki-rendering-xml. 3 public exploit references exist, so weaponization risk is real. A fix is available for org.xwiki.rendering:xwiki-rendering-xml — see the affected versions and patch details below.
org.xwiki.rendering:xwiki-rendering-xml Improper Neutralization of Invalid Characters in Identifiers in Web Pages vulnerability
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 CVE-2023-37908.
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
CVE-2023-37908 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 378,567 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-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
The cleaning of attributes during XHTML rendering, introduced in version 14.6-rc-1, allowed the injection of arbitrary HTML code and thus cross-site scripting via invalid attribute names. This can be exploited, e.g., via the link syntax in any content that supports XWiki syntax like comments in XWiki:
[[Link1>>https://XWiki.example.com||/onmouseover="alert('XSS1')"]]
When a user moves the mouse over this link, the malicious JavaScript code is executed in the context of the user session. When this user is a privileged user who has programming rights, this allows server-side code execution with programming rights, impacting the confidentiality, integrity and availability of the XWiki instance.
While this attribute was correctly recognized as not allowed, the attribute was still printed with a prefix data-xwiki-translated-attribute- without further cleaning or validation.
Note that while versions below 14.6 are not vulnerable to this particular vulnerability, they are still vulnerable to XSS through attributes in XWiki syntax, see the corresponding advisory.
Patches
This problem has been patched in XWiki 14.10.4 and 15.0 RC1 by removing characters not allowed in data attributes and then validating the cleaned attribute again.
Workarounds
There are no known workarounds apart from upgrading to a version including the fix.
References
- https://jira.xwiki.org/browse/XRENDERING-697
- https://github.com/xwiki/xwiki-rendering/commit/f4d5acac451dccaf276e69f0b49b72221eef5d2f
For more information
If you have any questions or comments about this advisory:
- Open an issue in Jira XWiki
- Email us at XWiki Security mailing-list
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.xwiki.rendering:xwiki-rendering-xml | ≥ 14.6-rc-1&&< 14.10.4 | 14.10.4org.xwiki.rendering:xwiki-rendering-xml:14.10.4 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.xwiki.rendering:xwiki-rendering-xml to 14.10.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-37908 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 CVE-2023-37908 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-37908. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-37908 in your dependencies?
O3 Security finds CVE-2023-37908 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.