GHSA-cv55-v6rw-7r5v
CRITICALXWiki Platform remote code execution from account via custom skins support
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.
Blast Radius
org.xwiki.platform:xwiki-platform-oldcore☕org.xwiki.platform:xwiki-platform-oldcore☕org.xwiki.platform:xwiki-platform-oldcoreReal-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
Any user who can edit any page like their profile can create a custom skin with a template override that is executed with programming right, thus allowing remote code execution.
To reproduce, as a user without edit, script or admin right, add an object of class XWiki.XWikiSkins to your profile. Name it whatever you want and set the Base Skin to flamingo.
Add an object of class XWikiSkinFileOverrideClass and set the path to macros.vm and the content to:
#macro(mediumUserAvatar $username)
#resizedUserAvatar($username 50)
$services.logging.getLogger('Skin').error("I got programming: $services.security.authorization.hasAccess('programming')")
#end
Back to your profile, click Test this skin. Force a refresh, just in case.
If the error "Skin - I got programming: true" gets logged, the installation is vulnerable.
Patches
This has been patched in XWiki 14.10.19, 15.5.4 and 15.10RC1.
Workarounds
We're not aware of any workaround except upgrading.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.xwiki.platform:xwiki-platform-oldcore | ≥ 6.4-milestone-1&&< 14.10.19 | 14.10.19 |
| ☕Maven | org.xwiki.platform:xwiki-platform-oldcore | ≥ 15.0-rc-1&&< 15.5.4 | 15.5.4 |
| ☕Maven | org.xwiki.platform:xwiki-platform-oldcore | ≥ 15.6-rc-1&&< 15.10-rc-1 | 15.10-rc-1 |
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 14.10.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cv55-v6rw-7r5v 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 GHSA-cv55-v6rw-7r5v 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 GHSA-cv55-v6rw-7r5v. 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-cv55-v6rw-7r5v in your dependencies?
O3 detects GHSA-cv55-v6rw-7r5v across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.