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WooCommerce Subscription < 9.1.0 — Unauthenticated PHP Object Injection

CVE-2026-18391Published · Updated

Action summary

Affected: <9.1.0Update to 9.1.0 or newer

All remediation steps
Watch plugin
Severity
Medium5.3
CVSS
5.3
CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
What does this vector mean?
AV:N Attack vector
Network
AC:L Attack complexity
Low
PR:N Privileges required
None
UI:N User interaction
None
S:U Scope
Unchanged
C:N Confidentiality
None
I:L Integrity
Low
A:N Availability
None
Weakness
CWE-502 PHP Object Injection
Required access
No account needed
Exploit prediction (EPSS)
No score
CISA KEV
Not listed
On this page8

Am I affected?

WooCommerce Subscription woocommerce-subscriptions

  1. Affected< 9.1.0
  2. Patched in9.1.0

Update to 9.1.0 or newer.

You are affected if you run < 9.1.0. Version 9.1.0 and later are not affected by this issue.

  • Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under WooCommerce Subscription.
  • No admin access? Run a passive check of your site. It reads public files only.
  • No account is needed to exploit this. Treat any exposed site on an affected version as at risk.

What to do

  1. Update to version 9.1.0, or a newer patched version
  2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
  3. Watch WooCommerce Subscription to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to Vasily Belolapotkov, Vlad Olaru.

The WooCommerce Subscription plugin for WordPress is vulnerable to PHP Object Injection in all versions up to 9.1.0 (exclusive) via deserialization of untrusted input. This makes it possible for unauthenticated attackers to inject a PHP Object. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

More in WooCommerce Subscription

All 6
More vulnerabilities in WooCommerce Subscription
SeverityVulnerabilityCVEPublished
Medium4.3Missing Authorization
<5.8.0Update to 5.8.0
CVE-2023-50850
Medium4.3Cross-Site Request Forgery
<4.6.0Update to 4.6.0
—
Medium6.5Missing Authorization to Insecure Direct Object Reference
≤5.1.2Update to 5.1.3
CVE-2023-35914
High8.3Cross-Site Request Forgery
<3.0.3Update to 3.0.3
—
Medium6.1Stored Cross-Site Scripting
<2.6.3Update to 2.6.3
CVE-2019-18834

Same weakness (PHP Object Injection)

All PHP Object Injection
Other PHP Object Injection vulnerabilities
SeverityVulnerabilityCVEPublished
High7.2Unauthenticated Stored Cross-Site Scripting via Comment User-Agent Header
EZ SQL Reports Shortcode Widget and DB Backup≤5.25.25Update to 5.26.45
CVE-2026-120688
Critical9.8Unauthenticated Arbitrary File Upload via File Upload via Public Form Submission
Chatterbug Forms – Fast, Flexible WordPress Form Builder≤1.0.2Update to 1.1
CVE-2026-125055
Critical9.8Unauthenticated PHP Object Injection to Remote Code Execution via 'form' Parameter
ELEX WordPress HelpDesk & Customer Ticketing System≤3.3.9Update to 3.4.0
CVE-2026-119077
Medium5.3Unauthenticated Sensitive Information Exposure in 'search' Parameter
Customer Reviews for WooCommerce≤5.127.0Update to 5.128.0
CVE-2026-121518

Timeline

  1. CVE published

    Severity medium, CVSS 5.3

  2. Record last updated

Sources & licenses

Wordfence record
Vulnerability data
Wordfence Intelligence. Copyright 2012-2026 Defiant Inc. Licensed under the CC BY-SA 4.0.
CVE® identifiers
Copyright 1999-2026 The MITRE Corporation. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
CVSS / CWE
National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.
VulnCrest content
Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.

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