PHP Object Injection Vulnerability in WooCommerce Subscriptions by WooCommerce
CVE-2026-18391

9.8CRITICAL

Key Information:

Vendor

WordPress
Status
WooCommerce Subscriptions
Vendor
CVE Published:
12 August 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-18391?

The WooCommerce Subscriptions plugin, prior to version 9.1.0, is vulnerable to PHP Object Injection when operating on stores that have High-Performance Order Storage enabled. This vulnerability allows unauthenticated users to exploit the weakness by injecting malicious serialized objects. By leveraging a gadget chain embedded in the plugin's dependencies, attackers can escalate their privileges to execute arbitrary code remotely, compromising the integrity and security of the affected site.

Affected Version(s)

WooCommerce Subscriptions 4.7.0 < 9.1.0

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-18391 - Proof of Concept

References

https://wpscan.com/vulnerability/191f76cf-e5bd-4a37-ac1c-...
exploitvdb-entrytechnical-description

CVSS V3.1

Score:
9.8
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Vasily Belolapotkov
Vlad Olaru
WPScan
.