PPWP – Password Protect Pages <= 1.9.18 - Authenticated (Contributor+) PHP Object Injection via post_protection_roles
Strategic Overview
- Status
- Patched in 1.9.19
- Affected Plugin
- PPWP – Password Protect Pages
- Affected Version
<= 1.9.18- CVSS
- 8.8High
- Weakness type
- CWE-502 · Deserialization of Untrusted Data
- CVE
CVE-2026-0551
At a glance
CVE-2026-0551 is a high-severity Deserialization of Untrusted Data vulnerability in the PPWP WordPress plugin, affecting versions <= 1.9.18. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account at Contributor level or above. The issue is fixed in version 1.9.19; sites on affected versions should update now. Disclosed August 2026, reported by Webbernaut.
Vulnerability Overview
The PPWP – Password Protect Pages plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 1.9.18 via deserialization of untrusted input from the 'post_protection_roles' vulnerable parameter. This makes it possible for authenticated attackers, with Contributor-level access and above, 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.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.
CWE-502: Deserialization of Untrusted Data
PPWP <= 1.9.18 carries this weakness at post_protection_roles, and reaching it takes an account at Contributor level or above. Deserialization of untrusted data means the application reconstructs objects from input a caller controls, letting the attacker choose which classes get instantiated and what their properties hold.
A workable chain turns deserialization into file writes, deletions or code execution, depending on what the loaded classes do in their magic methods. For PPWP the fix is 1.9.19: builds <= 1.9.18 are affected, anything from 1.9.19 onward is not.
Remediation
Update to version 1.9.19, or a newer patched version
How does WordSec protect against this?
An attacker needs Contributor access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: PPWP 1.9.19 closes this, and updating the plugin is the step that ends it.
- Firewall
- Scanner
- Alerts
External References
Related records
Other vulnerabilities in PPWP – Password Protect Pages
- 6.4CVE-2026-3639: PPWP – Password Protect Pages <= 1.9.21 Stored XSS
CVE-2026-3639 - 6.4CVE-2022-4626: PPWP – WordPress Password Protect Page Stored XSS
CVE-2022-4626 - 5.3CVE-2024-11280: PPWP Content Restriction Bypass to Info Exposure
CVE-2024-11280 - 5.3CVE-2024-0620: PPWP Protection Mechanism Bypass
CVE-2024-0620 - 4.3CVE-2025-11729: PPWP Improper Authorization
CVE-2025-11729 - 4.3CVE-2025-10005: Password Protect WordPress Lite IDOR
CVE-2025-10005 - 4.3CVE-2026-57634: PPWP – Password Protect Pages <= 1.9.19 IDOR
CVE-2026-57634 - 4.3CVE-2026-32562: PPWP – Password Protect Pages Missing Authorization
CVE-2026-32562
Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C