CVE-2026-5427: Auth Bypass (CVSS 5.3)

Description

The Kubio plugin for WordPress is vulnerable to Arbitrary File Upload in versions up to and including 2.7.2. This is due to insufficient capability checks in the kubio_rest_pre_insert_import_assets() function, which is hooked to the rest_pre_insert_{post_type} filter for posts, pages, templates, and template parts. When a post is created or updated via the REST API, Kubio parses block attributes looking for URLs in the 'kubio' attribute namespace and automatically imports them via importRemoteFile() without verifying the user has the upload_files capability. This makes it possible for authenticated attackers with Contributor-level access and above to bypass WordPress's normal media upload restrictions and upload files fetched from external URLs to the media library, creating attachment posts in the database.

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CVSS v3.1 Score

5.3

MEDIUM

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

EPSS — Exploit Prediction

0.0002

Probability of exploitation

0.04%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-862 Missing Authorization

References

Other References

https://plugins.trac.wordpress.org/browser/kubio/tags/2.7.1/lib/filters/post-insert.php#L17 https://plugins.trac.wordpress.org/browser/kubio/tags/2.7.1/lib/importer/importer-filters/kubio-blocks.php#L20 https://plugins.trac.wordpress.org/browser/kubio/tags/2.7.1/lib/src/Core/Importer.php#L546 https://plugins.trac.wordpress.org/browser/kubio/trunk/lib/filters/post-insert.php#L17 https://plugins.trac.wordpress.org/browser/kubio/trunk/lib/importer/importer-filters/kubio-blocks.php#L20 https://plugins.trac.wordpress.org/browser/kubio/trunk/lib/src/Core/Importer.php#L546 https://plugins.trac.wordpress.org/changeset/3506647/kubio/trunk/lib/src/Core/Importer.php https://www.wordfence.com/threat-intel/vulnerabilities/id/d8096f3c-e1a9-424f-af10-3e80212db985?source=cve

Frequently Asked Questions

What is CVE-2026-5427? +

The Kubio plugin for WordPress is vulnerable to Arbitrary File Upload in versions up to and including 2.7.2. This is due to insufficient capability checks in the kubio_rest_pre_insert_import_assets() function, which is hooked to the rest_pre_insert_{post_type} filter for posts, pages, templates, and template parts. When a post is created or updated via the REST API, Kubio parses block attributes looking for URLs in the 'kubio' attribute namespace and automatically imports them via importRemoteFile() without verifying the user has the upload_files capability. This makes it possible for authenticated attackers with Contributor-level access and above to bypass WordPress's normal media upload restrictions and upload files fetched from external URLs to the media library, creating attachment posts in the database. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-5427? +

CVE-2026-5427 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0002, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-5427? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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