Really Simple Security (Free) <= 9.8.2 - Unauthenticated Unbounded Option Growth
The Really Simple Security (Free) plugin for WordPress is vulnerable to Denial of Service in all versions up to, and including, 9.8.2. This is due to missing validation on client-supplied IP headers used as storage keys in the rsssl_404_cache option, allowing arbitrary values from HTTP_CLIENT_IP and HTTP_X_FORWARDED_FOR to be written as array keys without bound. This makes it possible for unauthenticated attackers to grow the rsssl_404_cache option without bound by supplying arbitrary values in spoofed client IP headers, degrading site performance when handling 404 responses.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | Really Simple Security – Simple and Performant Security (formerly Really Simple SSL) | <= 9.8.2 | 9.8.3 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L- Weakness (CWE)
CWE-400- Platform
- WordPress
- Package
Really Simple Security – Simple and Performant Security (formerly Really Simple SSL)- Disclosed
- 16.09.2026
- Updated
- 11.10.2026 10:23
Sources and licenses
Wordfence Intelligence - fbfd334c-dba4-49ec-b854-59e52236fe57 - Wordfence Intelligence
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Copyright 2012-2026 Defiant Inc.
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Vulnerability history: Really Simple Security – Simple and Performant Security (formerly Really Simple SSL)
All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 13
- First → latest
- 04.2024 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 2
- Medium 10
Disclosures per year
- 2024: 2
- 2025: 1
- 2026: 10
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Really Simple Security (Free) <= 9.8.2 - Unauthenticated Unbounded Option Growth this entry
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