CVE-2026-109306 craftcms CVE debrief

Who should care

Defenders responsible for Craft CMS installations, administrators, and security teams should be aware of this vulnerability and take necessary actions to mitigate it. They should prioritize verification, upgrading, and review of user permissions and access controls to prevent potential downgrades of the site edition. Additionally, they should monitor for suspicious activity and review compensating controls for exposed systems while remediation is scheduled

Why it matters

CVE-2026-109306 is a Medium-severity vulnerability in Craft CMS that allows authenticated users to change the installed edition, potentially downgrading the site edition. Defenders should prioritize verification, upgrading, and review of user permissions and access controls.

• Downgrade of site edition by authenticated users
• Potential persistence of unauthorized changes
• Need for verification of user permissions and access controls
• Requirement for upgrading to version 5.10.14 or later

Technical summary

The vulnerability exists in the AppController::actionSwitchToLicensedEdition() function, allowing any authenticated user to change the installed edition of Craft CMS. Low-privileged front-end users can exploit this vulnerability to persistently downgrade the site edition in project config, which admins cannot reverse from the control panel. This issue is particularly concerning for defenders responsible for Craft CMS installations, as it allows for potential downgrades of the site edition, which could lead to security risks.

Defensive priority

Defenders should prioritize verifying and upgrading to version 5.10.14 or later, and review user permissions and access controls.

Recommended defensive actions

• Verify and upgrade to version 5.10.14 or later
• Review user permissions and access controls
• Monitor for suspicious activity
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The CVE record and source item provide details on the vulnerability, including its description, CVSS score, and affected versions. The source item provides additional context on the vulnerability, including its impact on Craft CMS installations. The CVE Program record and NIST NVD detail page offer further information on the vulnerability and its severity. However, the exact scope of affected systems and potential impact on specific deployments is limited, requiring defenders to verify and review user permissions and access controls.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.