CVE-2025-39354 CRITICAL

CVE-2025-39354: WordPress Grand Conference theme <= 5.3 - PHP Object Injection vulnerability

Vendor Themegoods

Product Grand Conference

Weakness CWE-502 · Unsafe deserialization

Published May 19, 2025

Last update April 28, 2026

View on NVD All CVEs

CVSS base score

9.8/10

Attack vector Network

Attack complexity Low

Privileges required None

User interaction None

Confidentiality High

Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

What the vulnerability does

01Description

Deserialization of Untrusted Data vulnerability in ThemeGoods Grand Conference grandconference allows Object Injection.This issue affects Grand Conference: from n/a through <= 5.3.

Explanation of Vulnerability in Simple Terms

02Summary

Grand Conference versions 5.3 and earlier contain a deserialization vulnerability that allows unauthenticated attackers to execute arbitrary code on affected sites. The vulnerability exists in how the product processes untrusted serialized data without proper validation. No authentication or user interaction is required to exploit this issue.

What an attacker can do

03Attacker Capabilities

Run arbitrary code on the site and take complete control of it.

Potential impact on your site

04Site Impact

Complete compromise of the site, including data theft, malware injection, and site defacement.

Conditions required to exploit

05Prerequisites

Network access only; no authentication or user interaction required.

Key dates

06Disclosure timeline

May 19, 2025 CVE published

April 28, 2026 Record updated

External resources

07References

NVD — National Vulnerability Database https://nvd.nist.gov/vuln/detail/CVE-2025-39354 CWE — Common Weakness Enumeration https://cwe.mitre.org/data/definitions/502.html AskarLabs — CWE-502 write-up Deserialization of Untrusted Data

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