CVE-2025-66121

WordPress SiteGround Security plugin <= 1.5.8 - Broken Access Control vulnerability

5.3 Medium

Missing Authorization vulnerability in SiteGround SiteGround Security sg-security allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects SiteGround Security: from n/a through <= 1.5.8.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: Low

Exploit likelihood

0.32%Up 0.3 points since Dec 16, 2025

What each source reports

CVE List Score used 5.3

WordPress SiteGround Security plugin <= 1.5.8 - Broken Access Control vulnerability

Record: CVE-2025-66121
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness: CWE-862
Updated: 2026-11-02

EUVDEUVD-2025-203588 5.3

Record: EUVD-2025-203588
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated: 2026-11-02

GitHub AdvisoriesGHSA-j9wm-m2fc-3vmp 5.3

Missing Authorization vulnerability in SiteGround SiteGround Security sg-security allows...

Record: GHSA-j9wm-m2fc-3vmp
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness: CWE-862
Updated: 2026-11-02

NVD 5.3

Record: CVE-2025-66121
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness: CWE-862
Updated: 2026-11-02

Affected products

siteground security

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2025-66121 is a medium vulnerability (CVSS 5.3) in Siteground Security, published December 16, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.32%, the 25th percentile. No source names a fixed version.