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SiteGround Security EUVDEUVD-2026-68797

| CVE-2026-82228 HIGH
Authentication Bypass by Spoofing (CWE-290)
2026-08-31 Patchstack GHSA-72r6-f47g-xffm
8.1
CVSS 3.1 · Vendor: Patchstack
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Recon
    Identify WordPress site with SiteGround Security ≤ 1.6.6 and 2FA enabled
  2. Delivery
    Enumerate valid user account
  3. Exploit
    Initiate authentication flow
  4. Install
    Craft spoofed 2FA verification request (CWE-290)
  5. C2
    Bypass second-factor validation
  6. Execute
    Obtain authenticated WordPress session
  7. Impact
    Full site compromise

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Anti-spoofing controls
MITRE ATT&CK

1 technique across 1 tactic: Defense Evasion

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires a WordPress site with the SiteGround Security plugin installed and active in a version at or below 1.6.6, with two-factor authentication explicitly enabled and enforced for the targeted account. The CVSS vector (PR:N, UI:N) confirms no prior authentication or victim interaction is needed, but AC:H indicates a specific condition must be satisfied to trigger the spoofing - likely a crafted or precisely sequenced request that manipulates 2FA verification state. Sites using the SiteGround Security plugin without 2FA configured are not exposed to this specific attack vector. The attacker must be able to reach the WordPress login endpoint over the network, and must know or enumerate a valid account subject to 2FA enforcement.

Impact

The CVSS 8.1 score (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H) reflects a genuine high-severity risk: the vulnerability is network-accessible with no authentication prerequisite and no user interaction required, and successful exploitation yields full site compromise across confidentiality, integrity, and availability. The AC:H rating meaningfully limits risk by ruling out trivial mass-scanning exploits, suggesting that exploitation requires a targeted, crafted approach rather than opportunistic automation. EPSS data was not provided in the available intelligence, and the vulnerability does not appear in the CISA KEV catalog at time of analysis - meaning active exploitation has not been officially confirmed. No public POC has been identified, which further supports classifying this as a high-priority but not yet actively weaponized finding that warrants prompt patching for all operators with the 2FA feature enabled.

Exploit ScenarioDerived

An unauthenticated attacker targeting a WordPress site running SiteGround Security ≤ 1.6.6 with 2FA enabled initiates a login flow for a known or enumerated account, then crafts a spoofed or manipulated 2FA verification request that satisfies the plugin's (flawed) validation logic without possessing the actual one-time code. If the required attack complexity conditions are met, the attacker receives a fully authenticated session and gains administrative or user-level WordPress access. No public POC has been identified at time of analysis.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 31, 2026

Authentication bypass in the SiteGround Security WordPress plugin (versions ≤ 1.6.6) enables unauthenticated remote attackers to circumvent two-factor authentication protections and obtain fully authenticated WordPress sessions. Classified as CWE-290 (Authentication Bypass by Spoofing), this network-exploitable flaw carries a CVSS 8.1 score with full high impact across confidentiality, integrity, and availability, moderated only by elevated attack complexity (AC:H). No public exploit code or CISA KEV listing has been identified at time of analysis.

RemediationAI

Administrators should update the SiteGround Security plugin to the latest available release beyond version 1.6.6 immediately; however, no exact patched version number was confirmed in the available input data, and the Patchstack advisory at https://patchstack.com/database/wordpress/plugin/sg-security/vulnerability/wordpress-siteground-security-plugin-1-6-6-2fa-bypass-vulnerability should be consulted for the confirmed fix version before deploying. As a compensating control prior to patching, administrators may restrict access to wp-login.php via IP allowlist or firewall rules to reduce the network-accessible attack surface, though this does not eliminate the vulnerability and will impact legitimate remote logins. Temporarily disabling the SiteGround Security plugin's 2FA feature is a last-resort option that removes the vulnerable code path but eliminates the second authentication factor entirely, increasing overall exposure - only acceptable if paired with other compensating controls such as IP restrictions or a separate MFA solution.

Affected VersionsENISA

SiteGround Security n/a ≤1.6.6

Affected Packages

euvd siteground_security no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

SiteGround Security is a WordPress plugin (CPE: cpe:2.3:a:siteground:siteground_security) that provides site-hardening features including two-factor authentication. CWE-290 (Authentication Bypass by Spoofing) describes flaws in which an attacker circumvents authentication by forging or spoofing identity tokens, session state, or verification responses rather than supplying valid credentials. In this instance, the plugin's 2FA verification logic permits an unauthenticated party to manipulate or spoof the second-factor validation step, bypassing it entirely. The CVSS AC:H rating suggests exploitation requires a specific condition to trigger - potentially a crafted request sequence, timing dependency, or session-state manipulation that causes the spoofed response to be accepted as valid.

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Severity by source

Vendor (Patchstack) PRIMARY 8.1 HIGH
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 8.1 HIGH

Network-reachable login endpoint requires no credentials (PR:N) but elevated complexity to spoof 2FA state (AC:H); successful bypass yields full WordPress site compromise (C:H/I:H/A:H) within unchanged scope.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
4.0 AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (Patchstack).

CVSS VectorVendor: Patchstack

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionCVE.org

Unauthenticated Bypass Vulnerability in SiteGround Security <= 1.6.6 versions.

Executive ViewAI

Why It Matters

The SiteGround Security WordPress plugin (versions 1.6.6 and below) contains a high-severity authentication bypass flaw that allows unauthenticated attackers to circumvent two-factor authentication protections and establish fully authenticated WordPress sessions without valid credentials. Organizations relying on this plugin for access controls face immediate risk of unauthorized administrative access and potential data compromise. With no public exploit identified at time of analysis, prompt mitigation is critical to protect WordPress installations before threat actors develop weaponizable code.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis. Implement these interim mitigations: deactivate the vulnerable plugin and deploy alternative 2FA solutions immediately; configure Web Application Firewall (WAF) rules to detect anomalous authentication attempts; enforce strict rate limiting on login endpoints and restrict administrative access to known IP ranges; enable continuous monitoring and alerting on authentication logs; implement mandatory password resets for all administrative users and conduct periodic access reviews.

Threat Intelligence Overview

EPSS Score
0.2%
Top 86% exploitable
Prevalence
Medium
popular security plugin for SiteGround-hosted WordPress sites
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.2%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

40
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +40
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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