highCVE-2026-2354

Swiss Toolkit For WP <= 1.4.6 - Authenticated (Author+) Arbitrary File Upload via upload_extension_files()

Q: What is affected by CVE-2026-2354?

Swiss Toolkit For WP versions listed as affected should be reviewed: *-1.4.6.

Q: 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.

Q: 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.

Q: 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.

The Swiss Toolkit For WP plugin for WordPress is vulnerable to arbitrary file upload due to a flawed file type validation bypass in the `upload_extension_files()` function in all versions up to, and including, 1.4.6. The `upload_extension_files()` function hooks into WordPress's `wp_check_filetype_and_ext` filter and uses `strpos()` to check if a filename contains a configured extension string, rather than verifying the actual file extension. This makes it possible for authenticated attackers, with Author-level access and above, to upload arbitrary files (including PHP) on the affected site's server which may make remote code execution possible, granted the "Enhanced Multi-Format Image Support" feature is enabled with at least one extension (e.g., avif) in the allowed formats.

ProductSwiss Toolkit For WP

CVSS8.8

EPSS0.00553

UpdatedJuly 13, 2026

Quick answer

Swiss Toolkit For WP 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

*-1.4.6

Fixed versions

Apply the latest vendor-supported patched version.

How to fix it

Swiss Toolkit For WP is affected by CVE-2026-2354, a unsafe file upload issue in versions up to 1.4.6. No explicit patched version was available in the local Wordfence payload, so update to the latest vendor-supported patched release and verify against the linked advisory. Prioritize internet-facing WordPress sites, sites with public registration, customer portals, support, booking, import/export, page-builder, and admin workflows where the vulnerable feature is enabled. If immediate patching is not possible, disable the affected plugin or feature, restrict access, and monitor for exploitation until the update is installed.

Inventory every WordPress site that has Swiss Toolkit For WP installed, including production, staging, multisite, client, WooCommerce, support, booking, and content-management environments.
Confirm the installed Swiss Toolkit For WP version and compare it with the affected range from the Wordfence advisory.
Update Swiss Toolkit For WP to the latest vendor-supported patched release, or to a newer vendor-supported patched version from the official WordPress update channel.
If the update cannot be applied immediately, disable Swiss Toolkit For WP or the affected feature and restrict access with roles, authentication, WAF rules, or temporary route blocking.
Inspect upload directories, plugin storage paths, media folders, backups, snippets, and recently modified files for unexpected scripts, deleted files, webshells, or executable content.
Rotate administrator sessions, API keys, webhook secrets, payment or integration tokens, and affected credentials if logs or content review suggest compromise.
Clear WordPress, object, CDN, page-builder, security plugin, WooCommerce, booking/support plugin, and browser caches after patching so vulnerable assets or stored payloads are not served.

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Verify the fix

Confirm the running Swiss Toolkit For WP version is the latest vendor-supported patched release or newer, and record the patched version in the remediation ticket.
Verify unsafe file types cannot be uploaded or executed from user-writable paths after the update or mitigation.
Review web server, WordPress, security plugin, WAF, database, WooCommerce, booking/support, and application logs for exploitation attempts before and after the fix.
Retest normal visitor, subscriber, customer, editor, administrator, checkout, form, API, booking, support ticket, import/export, backup/restore, snippet, or integration workflows to confirm expected behavior still works.
Run a fresh Fixnx scan and document the public exposure state, patched version, log review, and any cleanup evidence.

Related categories

WordPress PHP Remote Code Execution File Upload Arbitrary File Write

Trusted references

Wordfence advisoryWordfence, NVD Source advisoryWordfence, NVD Source advisoryWordfence, NVD Source advisoryWordfence, NVD Source advisoryWordfence, NVD Source advisoryWordfence, NVD Wordfence advisoryWordfence, NVD

FAQ

What is affected by CVE-2026-2354?

Swiss Toolkit For WP versions listed as affected should be reviewed: *-1.4.6.

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.