CVE-2026-8365: CWE-502 Deserialization of Untrusted Data in creativethemeshq Blocksy
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().
AI Analysis
Technical Summary
CVE-2026-8365 describes a PHP Object Injection vulnerability in the Blocksy WordPress theme (creativethemeshq) affecting versions up to and including 2.1.35. The vulnerability arises from inadequate sanitization in the blocksy_sanitize_post_meta_options() function, which fails to block serialized PHP objects in post meta data. The SearchReplacer::run_recursively() function then deserializes all string values during the V200 database migration without restricting allowed classes. An attacker with contributor-level privileges can inject a serialized Blocksy\RaiiPattern object that triggers arbitrary PHP callable execution during the migration's object destruction phase, resulting in remote code execution.
Potential Impact
Successful exploitation allows an authenticated attacker with contributor-level access or higher to execute arbitrary PHP code on the server during the V200 migration process. This leads to full compromise of the affected WordPress site, including confidentiality, integrity, and availability impacts as indicated by the CVSS score of 8.8 (high severity).
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict contributor-level access to trusted users only and avoid running the V200 migration on untrusted data. Monitor the vendor's communications for patches or updates addressing this vulnerability.
CVE-2026-8365: CWE-502 Deserialization of Untrusted Data in creativethemeshq Blocksy
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().
CVSS v3.1
Score 8.8high
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-8365 describes a PHP Object Injection vulnerability in the Blocksy WordPress theme (creativethemeshq) affecting versions up to and including 2.1.35. The vulnerability arises from inadequate sanitization in the blocksy_sanitize_post_meta_options() function, which fails to block serialized PHP objects in post meta data. The SearchReplacer::run_recursively() function then deserializes all string values during the V200 database migration without restricting allowed classes. An attacker with contributor-level privileges can inject a serialized Blocksy\RaiiPattern object that triggers arbitrary PHP callable execution during the migration's object destruction phase, resulting in remote code execution.
Potential Impact
Successful exploitation allows an authenticated attacker with contributor-level access or higher to execute arbitrary PHP code on the server during the V200 migration process. This leads to full compromise of the affected WordPress site, including confidentiality, integrity, and availability impacts as indicated by the CVSS score of 8.8 (high severity).
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict contributor-level access to trusted users only and avoid running the V200 migration on untrusted data. Monitor the vendor's communications for patches or updates addressing this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Wordfence
- Date Reserved
- 2026-05-11T19:25:24.123Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a27e32c8dd33fbd851260e1
Added to database: 06/09/2026, 09:55:56 UTC
Last enriched: 06/09/2026, 10:10:40 UTC
Last updated: 07/31/2026, 19:23:00 UTC
Views: 61
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