WordPress security changelog
HIGH CVE-2026-8365 Deferred

Blocksy: Code execution

Blocksy is affected by code execution. Exploitation requires at least contributor-level access. Successful exploitation can run attacker-controlled code in the WordPress hosting account. The published affected range is <= 2.1.41.

CVE / CNA score 8.8 CVSS 3.1 · security@wordfence.com
NVD score Pending NVD has not published its own CVSS assessment.
Component
Blocksy
Plugin slug
blocksy
Affected
<= 2.1.41
Safe version
> 2.1.41
Published
Jun 09, 2026
Weakness
CWE-502 — Deserialization of Untrusted Data

This CVE was published Jun 09, 2026 and is one of 14 known issues for this theme.

What to do

Update, patch or deactivate.

Update Blocksy to a release after 2.1.41, or disable and remove it until a fixed version is available.

A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.

Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.

Source record

Technical description

The Blocksy theme for WordPress is vulnerable to PHP Object Injection leading to Remote Code Execution via the 'blocksy_meta' REST API field and the V200 database migration in versions up to and including 2.1.35. This is due to insufficient input sanitization in the blocksy_sanitize_post_meta_options() function, which only blocks values containing '<' or '>' and does not prevent serialized PHP object strings from being stored in post meta, combined with the SearchReplacer::run_recursively() function unconditionally deserializing all string values via @unserialize() during migration without restricting allowed classes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject a serialized Blocksy\RaiiPattern object into post meta that, when the V200 migration runs on an upgraded site, is deserialized and triggers RaiiPattern::__destruct(), which executes arbitrary PHP callables via call_user_func().

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

References

Primary and upstream sources