Medium severity · published Sep 18, 2026
CVE-2026-88798
Really Simple Security (Free) < 9.8.3 - Unauthenticated Unbounded Option Growth via Spoofed Client IP Header
5.3
CVSS
0.4%
EPSS
No
On KEV
Description
The Really Simple Security WordPress plugin before 9.8.3 does not validate a client-supplied address value before using it as a storage key in one of its own options, allowing unauthenticated attackers to grow that option without bound and to slow the site's handling of missing pages.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RS
Really Simple Security ·
8.1.6 before 9.8.3 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-88798
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-88798
wpscan.com
https://wpscan.com/vulnerability/e658dcd2-2ff6-4611-a28d-e2482c65be8b/
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