CVE-2026-8365: Blocksy (WordPress theme) · Deserialization of Untrusted Data
Affects Blocksy (WordPress theme)Source CVE Database V5
Not known to be exploited · CVSS 8.8 High.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 1.1% chance of exploitation in 30 days – higher than 66% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 9 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| creativethemeshqBlocksy | Affected
| Fixed in– |
AI-suggested
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.
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().
References
- wordfence.com/threat-intel/vulnerabilities/id/fd216743-ce8d-4632-9fd1-d63502c2dfcd?source=cve (opens in a new tab)
- themes.trac.wordpress.org/browser/blocksy/trunk/inc/classes/db-versioning/utils/db-search-replacer.php (opens in a new tab)
- themes.trac.wordpress.org/browser/blocksy/2.1.41/inc/classes/db-versioning/utils/db-search-replacer.php (opens in a new tab)
- themes.trac.wordpress.org/browser/blocksy/trunk/admin/helpers/meta-boxes.php (opens in a new tab)
- themes.trac.wordpress.org/browser/blocksy/2.1.41/admin/helpers/meta-boxes.php (opens in a new tab)
- themes.trac.wordpress.org/browser/blocksy/trunk/admin/helpers/validator.php (opens in a new tab)
- themes.trac.wordpress.org/browser/blocksy/2.1.41/admin/helpers/validator.php (opens in a new tab)
- themes.trac.wordpress.org/browser/blocksy/trunk/inc/classes/raii.php (opens in a new tab)
- themes.trac.wordpress.org/browser/blocksy/2.1.41/inc/classes/raii.php (opens in a new tab)
- themes.trac.wordpress.org/browser/blocksy/2.1.35/inc/classes/db-versioning/utils/db-search-replacer.php (opens in a new tab)
- themes.trac.wordpress.org/browser/blocksy/2.1.35/admin/helpers/meta-boxes.php (opens in a new tab)
- themes.trac.wordpress.org/browser/blocksy/2.1.35/admin/helpers/validator.php (opens in a new tab)
- themes.trac.wordpress.org/browser/blocksy/2.1.35/inc/classes/raii.php (opens in a new tab)