CVE-2026-33137: XWiki Platform has an Unauthenticated XAR Import via REST /wikis/{wikiName}
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.).
Other sources
XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. XWiki Platform is a generic wiki platform. In versions starting with 15.10.6 and prior to 18.1.0-rc-1, 17.10.3, 17.4.9, and 16.10.17, the POST /wikis/{wikiName} API executes a XAR import without performing any authentication or authorization checks, allowing an unauthenticated attacker to create or update documents in the target wiki. 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.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
maven/org.xwiki.platform:xwiki-platform-rest-serverto a version that resolves this vulnerability.Fixed in 18.1.0-rc-1 - Upgrade
Upgrade
maven/org.xwiki.platform:xwiki-platform-rest-serverto a version that resolves this vulnerability.Fixed in 17.10.3 - Upgrade
Upgrade
maven/org.xwiki.platform:xwiki-platform-rest-serverto a version that resolves this vulnerability.Fixed in 17.4.9 - Upgrade
Upgrade
maven/org.xwiki.platform:xwiki-platform-rest-serverto a version that resolves this vulnerability.Fixed in 16.10.17 - Upgrade
Upgrade
XWiki Platformto a version that resolves this vulnerability.Fixed in 16.10.17 - Upgrade
Upgrade
XWiki Platformto a version that resolves this vulnerability.Fixed in 17.4.9 - Upgrade
Upgrade
XWiki Platformto a version that resolves this vulnerability.Fixed in 17.10.3 - Upgrade
Upgrade
XWiki Platformto a version that resolves this vulnerability.Fixed in 18.0.1 - Upgrade
Upgrade
XWiki Platformto a version that resolves this vulnerability.Fixed in 18.1.0-rc-1 - Compensating control
Add an HTTP proxy rule to prevent access to POST requests in the `/wikis/{wikiName}[/]` endpoint (workaround mentioned in the advisory: block unauthenticated POST /wikis/{wikiName} which triggers the XAR import).
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33137?
CVE-2026-33137 is considered a high severity vulnerability due to its potential for unauthorized XAR imports via the REST API.
How do I fix CVE-2026-33137?
To fix CVE-2026-33137, upgrade XWiki Platform to version 18.1.0-rc-1 or later.
Which versions of XWiki are affected by CVE-2026-33137?
CVE-2026-33137 affects XWiki Platform versions prior to 16.10.17, 17.4.9, 17.10.3, and 18.0.1.
What type of vulnerability is CVE-2026-33137?
CVE-2026-33137 is an unauthenticated XAR import vulnerability which allows attackers to exploit the REST API.
Is authentication required to exploit CVE-2026-33137?
No, CVE-2026-33137 can be exploited without authentication, making it particularly dangerous.