Summary
XWiki Platform remote code execution from account via custom skins support
Workarounds
We're not aware of any workaround except upgrading.
References
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.
The application does not perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.
CVE-2024-31987 has a CVSS score of 9.9 (Critical). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (14.10.19, 15.5.4, 15.10-rc-1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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This has been patched in XWiki 14.10.19, 15.5.4 and 15.10RC1.
Frequently Asked Questions
- What is CVE-2024-31987? CVE-2024-31987 is a critical-severity missing authorization vulnerability in org.xwiki.platform:xwiki-platform-oldcore (maven), affecting versions >= 6.4-milestone-1, < 14.10.19. It is fixed in 14.10.19, 15.5.4, 15.10-rc-1. The application does not perform an authorization check before performing a sensitive operation.
- How severe is CVE-2024-31987? CVE-2024-31987 has a CVSS score of 9.9 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of org.xwiki.platform:xwiki-platform-oldcore are affected by CVE-2024-31987? org.xwiki.platform:xwiki-platform-oldcore (maven) versions >= 6.4-milestone-1, < 14.10.19 is affected.
- Is there a fix for CVE-2024-31987? Yes. CVE-2024-31987 is fixed in 14.10.19, 15.5.4, 15.10-rc-1. Upgrade to this version or later.
- Is CVE-2024-31987 exploitable, and should I be worried? Whether CVE-2024-31987 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2024-31987 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2024-31987?
- Upgrade
org.xwiki.platform:xwiki-platform-oldcoreto 14.10.19 or later - Upgrade
org.xwiki.platform:xwiki-platform-oldcoreto 15.5.4 or later - Upgrade
org.xwiki.platform:xwiki-platform-oldcoreto 15.10-rc-1 or later
- Upgrade