CVE-2021-29459
MEDIUMCVE-2021-29459 is a medium-severity (CVSS 6.1) 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-2021-29459 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
XSS Cross Site Scripting
Real-World Exposure
org.xwiki.platform:xwiki-platform-oldcore☕org.xwiki.platform:xwiki-platform-oldcore☕org.xwiki.platform:xwiki-platform-web☕org.xwiki.platform:xwiki-platform-webReal-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 Platform is a generic wiki platform offering runtime services for applications built on top of it. It is possible to persistently inject scripts in XWiki versions prior to 12.6.3 and 12.8. Unregistred users can fill simple text fields. Registered users can fill in their personal information and (if they have edit rights) fill the values of static lists using App Within Minutes. There is no easy workaround except upgrading XWiki. The vulnerability has been patched on XWiki 12.8 and 12.6.3.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.xwiki.platform:xwiki-platform-oldcore | all versions | 12.6.3 |
| ☕Maven | org.xwiki.platform:xwiki-platform-oldcore | ≥ 12.6.4&&< 12.8 | 12.8 |
| ☕Maven | org.xwiki.platform:xwiki-platform-web | all versions | 12.6.3 |
| ☕Maven | org.xwiki.platform:xwiki-platform-web | ≥ 12.6.4&&< 12.8 | 12.8 |
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 12.6.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-29459 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-2021-29459 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-2021-29459. 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-2021-29459 in your dependencies?
O3 detects CVE-2021-29459 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.