CVE-2026-40104: XWiki Platform Oldcore and Legacy Oldcore REST API Resource Exhaustion Vulnerability

org.xwiki.platform:xwiki-platform-oldcore Updated 15 Apr 2026

Summary

14/04/2026

Disclosed on

CVE-2026-40104

CVE

Yes i

Fix available

Moderate

Severity

6.9

CVSS Score

CVE-2026-40104: XWiki's REST APIs can list all pages/spaces, leading to unavailability. Affects org.xwiki.platform:xwiki-platform-oldcore across 3 version ranges.

>= 1.8-rc-1, < 16.10.16 >= 17.0.0-rc-1, < 17.4.8 >= 17.5.0-rc-1, < 17.10.1

Fixed in 16.10.16, 17.4.8 or 17.10.1, depending on the release line you run. How to fix ↓

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Background

XWiki is a powerful open-source platform designed for collaborative knowledge management. It allows users to create, edit, and manage content in a wiki format. The platform's REST APIs facilitate interaction with the wiki's data programmatically. However, certain endpoints can expose the system to resource exhaustion issues, particularly in large wikis, due to improper handling of database list properties.

Vulnerability Detail

The vulnerability arises from specific REST API endpoints that list all available pages and spaces, which can lead to resource exhaustion on large wikis. For instance, the endpoint '/xwiki/rest/wikis/xwiki/spaces/AnnotationCode/pages/AnnotationConfig/objects/AnnotationCode.AnnotationConfig/0/properties' retrieves extensive metadata, potentially overwhelming the server's resources and causing unavailability. This issue is classified under CWE-770, indicating improper handling of resource consumption.

How To Fix

Fixed versions by release line

The minimum fixed version depends on the release line you run.

>= 1.8-rc-1, < 16.10.16 16.10.16
>= 17.0.0-rc-1, < 17.4.8 17.4.8
>= 17.5.0-rc-1, < 17.10.1 17.10.1

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Workaround

Currently, there are no known workarounds other than upgrading the affected modules to the patched versions mentioned above.

Conclusion

In summary, CVE-2026-40104 poses a significant risk to XWiki installations, particularly those with extensive content. It is crucial to upgrade to the patched versions of the affected packages to mitigate this vulnerability and ensure the stability of your XWiki instance.

See every vulnerability recorded for org.xwiki.platform:xwiki-platform-oldcore →