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Stop Spammers Security <= 2022.5 — Unauthenticated PHP Object Injection

CVE-2022-4120Published · Updated

Action summary

Affected: ≤2022.5Update to 2022.6 or newer

All remediation steps
Watch plugin
Severity
Critical9.8
CVSS
9.8
CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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:H Confidentiality
High
I:H Integrity
High
A:H Availability
High
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?

Stop Spammers Classic stop-spammer-registrations-plugin

  1. Affected≤ 2022.5
  2. Patched in2022.6

Update to 2022.6 or newer.

You are affected if you run ≤ 2022.5. Version 2022.6 and later are not affected by this issue.

  • Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Stop Spammers Classic.
  • 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 2022.6, or a newer patched version
  2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
  3. Watch Stop Spammers Classic to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to Seryeon Ham.

The Stop Spammers Security plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 2022.5 via deserialization of untrusted input when issuing a CPATCHA challenge. This allows unauthenticated attackers to inject a PHP Object. No POP chain is present in the vulnerable plugin. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code. Note: The official PHP recommendation is not to pass untrusted input to unserialize even if the allowed_classes option is set to false.

Exploits & references

Proof-of-concept & detection

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

Advisories & patches

More in Stop Spammers Classic

All 10
More vulnerabilities in Stop Spammers Classic
SeverityVulnerabilityCVEPublished
Medium4.7Unauthenticated Stored Cross-Site Scripting via 'author' Parameter
≤2026.6Update to 2026.7
CVE-2026-120477
High7.2Unauthenticated Stored Cross-Site Scripting
≤2026.3Update to 2026.4
CVE-2026-48876
Medium4.3Cross-Site Request Forgery via Email Allowlist
≤2026.1Update to 2026.2
CVE-2025-14795
Medium5.4Cross-Site Request Forgery to Multiple Administrative Actions
≤2024.7Update to 2025
CVE-2025-2935
Medium5.4Cross-Site Request Forgery (CSRF) via sfs_process
≤2024.4Update to 2024.5
CVE-2023-7065

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 critical, CVSS 9.8

  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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