CVE-2021-43841 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in org.xwiki.platform:xwiki-platform-oldcore. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2021-43841 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Cross-site Scripting by SVG upload in xwiki-platform
Real-World Exposure
org.xwiki.platform:xwiki-platform-oldcore☕org.xwiki.platform:xwiki-platform-oldcore☕org.xwiki.platform:xwiki-platform-tool-configuration-resources☕org.xwiki.platform:xwiki-platform-tool-configuration-resourcesReal-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
XWiki is a generic wiki platform offering runtime services for applications built on top of it. When using default XWiki configuration, it's possible for an attacker to upload an SVG containing a script executed when executing the download action on the file. This problem has been patched so that the default configuration doesn't allow to display the SVG files in the browser. Users are advised to update or to disallow uploads of SVG files.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.xwiki.platform:xwiki-platform-oldcore | all versions | 12.10.6 |
| ☕Maven | org.xwiki.platform:xwiki-platform-oldcore | ≥ 13.0&&< 13.3RC1 | 13.3RC1 |
| ☕Maven | org.xwiki.platform:xwiki-platform-tool-configuration-resources | ≥ 13.0&&< 13.3RC1 | 13.3RC1 |
| ☕Maven | org.xwiki.platform:xwiki-platform-tool-configuration-resources | all versions | 12.10.6 |
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.platform:xwiki-platform-oldcore. 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.platform:xwiki-platform-oldcore to 12.10.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-43841 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 CVE-2021-43841 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 CVE-2021-43841. 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-2021-43841 in your dependencies?
O3 detects CVE-2021-43841 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.