How severe is CVE-2026-40104?

No CVSS score has been assigned to CVE-2026-40104 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-40104?

CVE-2026-40104 affects the following packages: org.xwiki.platform:xwiki-platform-oldcore (Maven), org.xwiki.platform:xwiki-platform-oldcore (Maven), org.xwiki.platform:xwiki-platform-oldcore (Maven), org.xwiki.platform:xwiki-platform-legacy-oldcore (Maven), org.xwiki.platform:xwiki-platform-legacy-oldcore (Maven), org.xwiki.platform:xwiki-platform-legacy-oldcore (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-40104?

Update org.xwiki.platform:xwiki-platform-oldcore to 16.10.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40104 is resolved across your whole dependency graph.

How do I detect CVE-2026-40104 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.xwiki.platform:xwiki-platform-oldcore, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-40104 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2026-40104 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-40104 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-40104?

CVE-2026-40104 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 34th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-40104?

CVE-2026-40104 is classified as CWE-770 (CWE-770). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-40104 published, and has it been updated?

CVE-2026-40104 was published on April 15, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-40104: xwiki-platform DoS

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-40104.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs34th percentile — riskier than 34% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

6 pkgs affected

☕org.xwiki.platform:xwiki-platform-oldcore☕org.xwiki.platform:xwiki-platform-oldcore☕org.xwiki.platform:xwiki-platform-oldcore☕org.xwiki.platform:xwiki-platform-legacy-oldcore☕org.xwiki.platform:xwiki-platform-legacy-oldcore☕org.xwiki.platform:xwiki-platform-legacy-oldcore

Real-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. Versions 1.8-rc-1, 17.0.0-rc-1 and 17.5.0-rc-1 and prior include a resource exhaustion vulnerability in REST API endpoints such as /xwiki/rest/wikis/xwiki/spaces/AnnotationCode/pages/AnnotationConfig/objects/AnnotationCode.AnnotationConfig/0/properties, which list all available pages as part of the metadata for database list properties without applying query limits. On large wikis, this can exhaust available server resources. This issue has been patched in versions 16.10.16, 17.4.8 and 17.10.1.

Affected Packages

6 total 6 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.xwiki.platform:xwiki-platform-oldcore`	≥ 1.8-rc-1&&< 16.10.16	16.10.16`org.xwiki.platform:xwiki-platform-oldcore:16.10.16`
☕Maven	`org.xwiki.platform:xwiki-platform-oldcore`	≥ 17.0.0-rc-1&&< 17.4.8	17.4.8`org.xwiki.platform:xwiki-platform-oldcore:17.4.8`
☕Maven	`org.xwiki.platform:xwiki-platform-oldcore`	≥ 17.5.0-rc-1&&< 17.10.1	17.10.1`org.xwiki.platform:xwiki-platform-oldcore:17.10.1`
☕Maven	`org.xwiki.platform:xwiki-platform-legacy-oldcore`	≥ 1.8-rc-1&&< 16.10.16	16.10.16`org.xwiki.platform:xwiki-platform-legacy-oldcore:16.10.16`
☕Maven	`org.xwiki.platform:xwiki-platform-legacy-oldcore`	≥ 17.0.0-rc-1&&< 17.4.8	17.4.8`org.xwiki.platform:xwiki-platform-legacy-oldcore:17.4.8`
☕Maven	`org.xwiki.platform:xwiki-platform-legacy-oldcore`	≥ 17.5.0-rc-1&&< 17.10.1	17.10.1`org.xwiki.platform:xwiki-platform-legacy-oldcore:17.10.1`

Affected Products

1 product · 3 configurations

Application

xwikixwiki

≥ 17.5.0 && < 17.10.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.xwiki.platform:xwiki-platform-oldcore, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.xwiki.platform:xwiki-platform-oldcore to 16.10.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40104 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. Versions 1.8-rc-1, 17.0.0-rc-1 and 17.5.0-rc-1 and prior include a resource exhaustion vulnerability in REST API endpoints such as /xwiki/rest/wikis/xwiki/spaces/AnnotationCode/pages/AnnotationConfig/objects/AnnotationCode.AnnotationConfig/0/properties, which list all available pages as part of the metadata for database list properties without applying query limits. On large wikis, this can exhaust available server resources. This issue has been patched in versions 16.10.16, 17.4.8 and 17.1

O3 Security · Impact-Aware SCA

Is CVE-2026-40104 in your dependencies?

Find it across Maven, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVE-2026-40104 — xwiki-platform-oldcore