CVE-2021-24307: All in One SEO Pack < 4.1.0.2 - Admin RCE via unserialize

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 53.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-05-24 · updated 2026-06-17
Weakness: CWE-502

Description

The All in One SEO – Best WordPress SEO Plugin – Easily Improve Your SEO Rankings before 4.1.0.2 enables authenticated users with "aioseo_tools_settings" privilege (most of the time admin) to execute arbitrary code on the underlying host. Users can restore plugin's configuration by uploading a backup .ini file in the section "Tool > Import/Export". However, the plugin attempts to unserialize values of the .ini file. Moreover, the plugin embeds Monolog library which can be used to craft a gadget chain and thus trigger system command execution.

Affected products

smub All in One SEO – Powerful SEO Plugin to Boost SEO Rankings & Increase Traffic: before 4.1.0.2 — fixed in 4.1.0.2

How to fix

Upgrade to a fixed version: smub All in One SEO – Powerful SEO Plugin to Boost SEO Rankings & Increase Traffic 4.1.0.2. Check the vendor advisory for mitigations.

References

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