CVE-2023-40555: WordPress Flatsome Theme <= 3.17.5 is vulnerable to PHP Object Injection

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-12-20 · updated 2026-06-17
Weakness: CWE-502

Description

Deserialization of Untrusted Data vulnerability in UX-themes Flatsome | Multi-Purpose Responsive WooCommerce Theme.This issue affects Flatsome | Multi-Purpose Responsive WooCommerce Theme: from n/a through 3.17.5.

Affected products

UX-themes Flatsome: before 3.17.6 — fixed in 3.17.6

How to fix

Upgrade to a fixed version: UX-themes Flatsome 3.17.6. Check the vendor advisory for mitigations.

References

https://patchstack.com/database/vulnerability/flatsome/wordpress-flatsome-theme-3-17-5-unauthenticated-php-object-injection-vulnerability?_s_id=cve
https://patchstack.com/database/vulnerability/flatsome/wordpress-flatsome-theme-3-17-5-unauthenticated-php-object-injection-vulnerability?_s_id=cve

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