{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-8365: Blocksy <= 2.1.41 - Authenticated (Contributor+) PHP Object Injection via Deserialization of Untrusted Data via 'blocksy_meta' REST API Field","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-8365","status":"final","version":"1","initial_release_date":"2026-06-09T08:29:40.638Z","current_release_date":"2026-06-09T12:56:15.813Z","revision_history":[{"date":"2026-06-09T08:29:40.638Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"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().","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-8365 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-8365"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-8365"},{"category":"external","summary":"wordfence.com","url":"https://www.wordfence.com/threat-intel/vulnerabilities/id/fd216743-ce8d-4632-9fd1-d63502c2dfcd?source=cve"},{"category":"external","summary":"themes.trac.wordpress.org","url":"https://themes.trac.wordpress.org/browser/blocksy/trunk/inc/classes/db-versioning/utils/db-search-replacer.php#L98"},{"category":"external","summary":"themes.trac.wordpress.org","url":"https://themes.trac.wordpress.org/browser/blocksy/2.1.41/inc/classes/db-versioning/utils/db-search-replacer.php#L98"},{"category":"external","summary":"themes.trac.wordpress.org","url":"https://themes.trac.wordpress.org/browser/blocksy/trunk/admin/helpers/meta-boxes.php#L104"},{"category":"external","summary":"themes.trac.wordpress.org","url":"https://themes.trac.wordpress.org/browser/blocksy/2.1.41/admin/helpers/meta-boxes.php#L104"},{"category":"external","summary":"themes.trac.wordpress.org","url":"https://themes.trac.wordpress.org/browser/blocksy/trunk/admin/helpers/validator.php#L75"},{"category":"external","summary":"themes.trac.wordpress.org","url":"https://themes.trac.wordpress.org/browser/blocksy/2.1.41/admin/helpers/validator.php#L75"},{"category":"external","summary":"themes.trac.wordpress.org","url":"https://themes.trac.wordpress.org/browser/blocksy/trunk/inc/classes/raii.php#L12"},{"category":"external","summary":"themes.trac.wordpress.org","url":"https://themes.trac.wordpress.org/browser/blocksy/2.1.41/inc/classes/raii.php#L12"},{"category":"external","summary":"themes.trac.wordpress.org","url":"https://themes.trac.wordpress.org/browser/blocksy/2.1.35/inc/classes/db-versioning/utils/db-search-replacer.php#L98"},{"category":"external","summary":"themes.trac.wordpress.org","url":"https://themes.trac.wordpress.org/browser/blocksy/2.1.35/admin/helpers/meta-boxes.php#L104"},{"category":"external","summary":"themes.trac.wordpress.org","url":"https://themes.trac.wordpress.org/browser/blocksy/2.1.35/admin/helpers/validator.php#L75"},{"category":"external","summary":"themes.trac.wordpress.org","url":"https://themes.trac.wordpress.org/browser/blocksy/2.1.35/inc/classes/raii.php#L12"}]},"product_tree":{"branches":[{"category":"vendor","name":"creativethemeshq","branches":[{"category":"product_name","name":"Blocksy","branches":[{"category":"product_version_range","name":"<=2.1.41","product":{"name":"creativethemeshq Blocksy <=2.1.41","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:creativethemeshq:blocksy:*:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-8365","title":"Blocksy <= 2.1.41 - Authenticated (Contributor+) PHP Object Injection via Deserialization of Untrusted Data via 'blocksy_meta' REST API Field","notes":[{"category":"description","text":"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().","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"},"products":["CSAFPID-1"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1"]}]}]}