Deserialization of untrusted data in creativethemeshq Blocksy
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-502.
Summary
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().
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| creativethemeshq | Blocksy | up to 2.1.41 | — | No fix listed | CNA |
- Blocksy Vendorcreativethemeshq Affected up to 2.1.41 Fixed in — No fix listed CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:creativethemes:blocksy:*:*:*:*:*:*:*:* | — | — | creativethemeshq |
- cpe:2.3:a:creativethemes:blocksy:*:*:*:*:*:*:*:* Versions — — ·creativethemeshq
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-8365
- 2026-10-03 Alias added: GHSA-r622-c48h-h6qq
References
Other 13
- https://www.wordfence.com/threat-intel/vulnerabilities/id/fd216743-ce8d-4632-9fd1-d63502c2dfcd?source=cve
- https://themes.trac.wordpress.org/browser/blocksy/trunk/inc/classes/db-versioning/utils/db-search-replacer.php#L98
- https://themes.trac.wordpress.org/browser/blocksy/2.1.41/inc/classes/db-versioning/utils/db-search-replacer.php#L98
- https://themes.trac.wordpress.org/browser/blocksy/trunk/admin/helpers/meta-boxes.php#L104
- https://themes.trac.wordpress.org/browser/blocksy/2.1.41/admin/helpers/meta-boxes.php#L104
- https://themes.trac.wordpress.org/browser/blocksy/trunk/admin/helpers/validator.php#L75
- https://themes.trac.wordpress.org/browser/blocksy/2.1.41/admin/helpers/validator.php#L75
- https://themes.trac.wordpress.org/browser/blocksy/trunk/inc/classes/raii.php#L12
- https://themes.trac.wordpress.org/browser/blocksy/2.1.41/inc/classes/raii.php#L12
- https://themes.trac.wordpress.org/browser/blocksy/2.1.35/inc/classes/db-versioning/utils/db-search-replacer.php#L98
- https://themes.trac.wordpress.org/browser/blocksy/2.1.35/admin/helpers/meta-boxes.php#L104
- https://themes.trac.wordpress.org/browser/blocksy/2.1.35/admin/helpers/validator.php#L75
- https://themes.trac.wordpress.org/browser/blocksy/2.1.35/inc/classes/raii.php#L12
More creativethemeshq vulnerabilities
- TI-2026-42084 Blocksy Companion Pro < 2.1.47 Unauthenticated File Upload via save_attachments CVSS 4.0CRITICAL 9.2
- TI-2023-01796 Blocksy Companion < 1.8.82 - Subscriber+ Draft Post Access CVSS 3.1MEDIUM 4.3
- TI-2026-12769 Blocksy Companion <= 2.1.46 - Unauthenticated Arbitrary File Upload via 'blc-review-images[]' Parameter CVSS 3.1CRITICAL 9.8
- TI-2026-41450 WordPress Blocksy Companion Pro plugin <= 2.1.46 - Remote Code Execution (RCE) vulnerability CVSS 3.1CRITICAL 10.0
- TI-2026-70281 Unauthenticated privilege escalation in Blocksy Companion CVSS 3.1CRITICAL 9.1
- TI-2026-28570 WordPress Blocksy Companion Pro plugin < 2.1.29 - SQL Injection vulnerability CVSS 3.1CRITICAL 9.3
Sources
- CVE-2026-8365 · CVE Program
- CVE-2026-8365 · NVD
- FIRST EPSS
- GHSA-r622-c48h-h6qq · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences