XWiki Platform has an Unauthenticated XAR Import via REST /wikis/{wikiName}

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

9.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-33137: 0.59% estimated exploitation activity in the next 30 days; percentile 48.46 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact POST /wikis/{wikiName} executes a XAR import without performing any authentication or authorization checks, allowing an unauthenticated attacker to create or update documents in the target wiki Patches This vulnerability has been patched in XWiki 16.10.17, 17.4.9, 17.10.3, 18.0.1 and 18.1.0-rc-1. Workarounds XWiki is not aware of any workarounds other than adding a rule into an HTTP proxy to prevent access POST request in the /wikis/{wikiName}[/] endpoint. Resources https://jira.xwiki.org/browse/XWIKI-23953 https://github.com/xwiki/xwiki-platform/commit/4b7b95b79256374d487e9ece1dc48f527966990f For more information If there are any questions or comments about this advisory: Open an issue in Jira XWiki.org Send an email to the Security Mailing List Attribution Reported by Sho Odagiri (GMO Cybersecurity by Ierae, Inc.).

Published by the source

26 May 2026, 18:58 UTC

Last modified by the source

26 May 2026, 18:58 UTC

Source last checked

26 Oct 2026, 16:45 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-qrvh-r3f2-9h4r

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# Patch Next advisory brief: CVE-2026-33137

Advisory: XWiki Platform has an Unauthenticated XAR Import via REST /wikis/{wikiName}
IDs: CVE-2026-33137, GHSA-qrvh-r3f2-9h4r
Record: https://patchnext.com/advisories/cve-2026-33137 (revision 1, source checked 26 Oct 2026, 16:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.xwiki.platform:xwiki-platform-rest-server 18.1.0-rc-1, 17.10.3, 17.4.9, 16.10.17. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.xwiki.platform:xwiki-platform-rest-server: affected >= 15.10.6, < 16.10.17; >= 17.0.0-rc-1, < 17.4.9; >= 17.5.0, < 17.10.3; >= 18.0.0-rc-1, < 18.1.0-rc-1; fixed in 16.10.17, 17.4.9, 17.10.3, 18.1.0-rc-1

## Suggested inspection (read-only)
- Maven org.xwiki.platform:xwiki-platform-rest-server: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.xwiki.platform:xwiki-platform-rest-server.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-qrvh-r3f2-9h4r (GitHub-reviewed advisory GHSA-qrvh-r3f2-9h4r lists affected ranges: Maven org.xwiki.platform:xwiki-platform-rest-server >=15.10.6 =17.0.0-rc-1 =17.5.0 =18.0.0-rc-1 <18.1.0-rc-1)

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