CVE-2026-8365
Blocksy <= 2.1.41 - Authenticated (Contributor+) PHP Object Injection via Deserialization of Untrusted Data via 'blocksy_meta' REST API Field
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().
INFO
Published Date :
June 9, 2026, 9:16 a.m.
Last Modified :
June 9, 2026, 9:16 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-8365
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update the Blocksy theme to version 2.1.36 or later.
- Verify database migration has completed successfully.
- Review post meta for suspicious serialized objects.
- Remove any unauthorized serialized objects.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-8365.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-8365 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-8365
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-8365 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-8365 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Jun. 09, 2026
Action Type Old Value New Value Added 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(). Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-502 Added Reference https://themes.trac.wordpress.org/browser/blocksy/2.1.35/admin/helpers/meta-boxes.php#L104 Added Reference https://themes.trac.wordpress.org/browser/blocksy/2.1.35/admin/helpers/validator.php#L75 Added Reference https://themes.trac.wordpress.org/browser/blocksy/2.1.35/inc/classes/db-versioning/utils/db-search-replacer.php#L98 Added Reference https://themes.trac.wordpress.org/browser/blocksy/2.1.35/inc/classes/raii.php#L12 Added Reference https://themes.trac.wordpress.org/browser/blocksy/2.1.41/admin/helpers/meta-boxes.php#L104 Added Reference https://themes.trac.wordpress.org/browser/blocksy/2.1.41/admin/helpers/validator.php#L75 Added Reference https://themes.trac.wordpress.org/browser/blocksy/2.1.41/inc/classes/db-versioning/utils/db-search-replacer.php#L98 Added Reference https://themes.trac.wordpress.org/browser/blocksy/2.1.41/inc/classes/raii.php#L12 Added Reference https://themes.trac.wordpress.org/browser/blocksy/trunk/admin/helpers/meta-boxes.php#L104 Added Reference https://themes.trac.wordpress.org/browser/blocksy/trunk/admin/helpers/validator.php#L75 Added Reference https://themes.trac.wordpress.org/browser/blocksy/trunk/inc/classes/db-versioning/utils/db-search-replacer.php#L98 Added Reference https://themes.trac.wordpress.org/browser/blocksy/trunk/inc/classes/raii.php#L12 Added Reference https://www.wordfence.com/threat-intel/vulnerabilities/id/fd216743-ce8d-4632-9fd1-d63502c2dfcd?source=cve