Themify Builder <= 7.7.7 - Missing Authorization to Authenticated (Subscriber+) Arbitrary Post Stylesheet Write/Delete via tb_generate_on_fly AJAX Action
The Themify Builder plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 7.7.7. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for authenticated attackers, with subscriber-level access and above, to overwrite or delete the generated CSS stylesheet file of arbitrary posts, including private and draft posts owned by other users, and modify plugin-scoped font options. The required CSRF nonce (tf_nonce) is emitted on public front-end builder pages via wp_localize_script, making it trivially obtainable by any authenticated user visiting such a page.
Quick answer
Themify Builder should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- *-7.7.7
Fixed versions
- 7.7.8
How to fix it
Themify Builder is affected by this security issue. The safest fix is to update to the fixed version, then test the site or service again to make sure the risky path is closed.
- Find every place where Themify Builder is installed or used.
- Update to 7.7.8 or a later vendor-supported version.
- Back up the site or service before changing production systems.
- Apply the update in staging first if possible, then deploy it to production.
- If you cannot update right away, restrict access to the affected feature and monitor logs closely.
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Verify the fix
- Confirm the installed version or configuration is no longer in the affected range.
- Retest the affected page, API, plugin, workflow, or network path.
- Check logs after the change for blocked attempts, crashes, or errors.
- Run a fresh Fixnx scan and save the report.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-15407?
Themify Builder versions listed as affected should be reviewed: *-7.7.7.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.