CVE-2026-18391Network attack vector

Unauthenticated RCE via unvalidated PHP deserialization

Published Aug 12, 2026 · Updated Aug 12, 2026

PHP object injection in WooCommerce Subscriptions before 9.1.0 allows remote attackers to execute arbitrary code without authentication. With HPOS enabled, an undisclosed request path passes unvalidated user input to PHP unserialize(), creating objects through a gadget chain in bundled dependencies. No account or user interaction is required, and successful exploitation grants code execution with the privileges of the WordPress service.

CVSS severity9.8
Critical
EPSS probability0.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

PHP object injection in WooCommerce Subscriptions before 9.1.0 allows remote attackers to execute arbitrary code without authentication. With HPOS enabled, an undisclosed request path passes unvalidated user input to PHP unserialize(), creating objects through a gadget chain in bundled dependencies. No account or user interaction is required, and successful exploitation grants code execution with the privileges of the WordPress service.

The record

CVE
CVE-2026-18391
Published
Aug 12, 2026
Updated
Aug 12, 2026
Vendor
WooCommerce
Product
WooCommerce Subscriptions
Classifications
CWE-94, CWE-434, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.7.0 <9.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

WooCommerce · WooCommerce Subscriptionsversion=4.7.0 <9.1.0

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
CWE-434Unrestricted Upload of File with Dangerous Type
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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