creativethemeshq Blocksy Plugin up to 2.1.41 on WordPress blocksy_sanitize_post_meta_options deserialization

Summaryinfo

A vulnerability described as critical has been identified in creativethemeshq Blocksy Plugin up to 2.1.41 on WordPress. This issue affects the function blocksy_sanitize_post_meta_options. Executing a manipulation can lead to deserialization. This vulnerability is tracked as CVE-2026-8365. The attack can be launched remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in creativethemeshq Blocksy Plugin up to 2.1.41 on WordPress and classified as critical. This vulnerability affects the function blocksy_sanitize_post_meta_options. The manipulation with an unknown input leads to a deserialization vulnerability. The CWE definition for the vulnerability is CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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 '' 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().

The weakness was disclosed by Quốc Huy. The advisory is shared for download at wordfence.com. This vulnerability was named CVE-2026-8365 since 05/11/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available.

Upgrading eliminates this vulnerability.

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Productinfo

Type

• WordPress Plugin

Vendor

• creativethemeshq

Name

• Blocksy Plugin

Version

• 2.1.0
• 2.1.1
• 2.1.2
• 2.1.3
• 2.1.4
• 2.1.5
• 2.1.6
• 2.1.7
• 2.1.8
• 2.1.9
• 2.1.10
• 2.1.11
• 2.1.12
• 2.1.13
• 2.1.14
• 2.1.15
• 2.1.16
• 2.1.17
• 2.1.18
• 2.1.19
• 2.1.20
• 2.1.21
• 2.1.22
• 2.1.23
• 2.1.24
• 2.1.25
• 2.1.26
• 2.1.27
• 2.1.28
• 2.1.29
• 2.1.30
• 2.1.31
• 2.1.32
• 2.1.33
• 2.1.34
• 2.1.35
• 2.1.36
• 2.1.37
• 2.1.38
• 2.1.39
• 2.1.40
• 2.1.41

CPE 2.3info

• 🔒
• 🔒
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CPE 2.2info

• 🔒
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Entryinfo

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