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CVE-2026-2354

HIGHCVSS 8.8/10EPSS 0.55%

Last modified

CVE-2026-2354 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. 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. EPSS estimates a 0.55% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.55%

42.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
wpmessiahSwiss Toolkit For WP<= 1.4.6

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-2354?
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.
How severe is CVE-2026-2354?
CVE-2026-2354 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.55% probability of exploitation in the next 30 days.
How do I fix CVE-2026-2354?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST