CVE-2022-4120: Stop Spammers Security < 2022.6 - Unauthenticated PHP Object Injection

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 18.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2022-12-26 · updated 2026-06-17

Description

The Stop Spammers Security | Block Spam Users, Comments, Forms WordPress plugin before 2022.6 passes base64 encoded user input to the unserialize() PHP function when CAPTCHA are used as second challenge, which could lead to PHP Object injection if a plugin installed on the blog has a suitable gadget chain

Affected products

Stop Spammers Security | Block Spam Users, Comments, Forms: before 2022.6 — fixed in 2022.6

How to fix

Upgrade to a fixed version: Stop Spammers Security | Block Spam Users, Comments, Forms 2022.6. Check the vendor advisory for mitigations.

References

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