CVE-2026-89145 flextype CVE debrief

Who should care

Defenders responsible for Flextype CMS installations, particularly those with write access to the plugins directory, should assess exposure and verify proper HTML escaping of plugin directory names to prevent potential script execution.

Why it matters

Defenders should care about CVE-2026-89145 because it allows attackers with write access to plugin directories to potentially execute scripts in users' browsers. This requires verification of plugin directory names and proper HTML escaping to prevent script execution. Affected roles include developers and administrators of Flextype CMS installations. The vulnerability has a CVSS score of 2.4 and is considered low severity.

• Potential script execution in users' browsers when dependency validation fails
• Possible data theft or unauthorized actions through XSS
• Required verification of plugin directory names for proper HTML escaping
• Necessity to restrict write access to plugins directory

Technical summary

Flextype CMS versions 0.9.9 through 1.0.0-alpha.3 do not HTML-escape plugin directory names in the dependency error page rendered by getValidPluginsDependencies(). This allows attackers with write access to the plugins directory to create a plugin with HTML characters in its name, potentially leading to script execution in users' browsers when dependency validation fails. The vulnerability has a CVSS score of 2.4 and is considered low severity. Defenders should prioritize verifying plugin directory names and ensuring proper HTML escaping to prevent potential script execution.

Defensive priority

Defenders should prioritize verifying plugin directory names and ensuring proper HTML escaping to prevent potential script execution.

Recommended defensive actions

• Verify plugin directory names for proper HTML escaping
• Ensure write access to plugins directory is restricted
• Monitor for suspicious plugin directory name changes
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description and affected versions. Flextype CMS versions 0.9.9 through 1.0.0-alpha.3 are confirmed affected. Defenders should verify plugin directory names and ensure proper HTML escaping to prevent potential script execution. Evidence is limited to public CVE and NVD records.

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.