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MasterStudy LMS CVE-2026-88846

| EUVDEUVD-2026-85803 MEDIUM
Missing Authorization (CWE-862)
2026-09-24 WPScan GHSA-4mwj-c7j6-fqvw
5.3
CVSS 3.1 · Vendor: WPScan
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Attack ChainAIDerived

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

  1. Access
    Identify site with registration disabled
  2. Exploit
    Submit front-end registration request
  3. Impact
    Obtain auto-logged-in account bypassing policy

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization checks on every request
MITRE ATT&CK

1 technique across 1 tactic: Privilege Escalation

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

Exploitation Conditions

Requires the MasterStudy LMS plugin (versions 2.3.0 through before 3.7.50) installed and active, and - critically - the site administrator must have deliberately DISABLED user registration; on sites where registration is left enabled the behavior grants nothing beyond intended self-registration, so there is no security consequence. No authentication, no user interaction, and no special platform configuration is otherwise needed: exploitation is via the plugin's unauthenticated front-end registration flow. The limiting factor is therefore the site's registration-disabled configuration, which defines where the flaw actually matters; impact is capped at subscriber-level account creation (I:L), with no confidentiality or availability effect.

Impact

This is a genuine but low-to-moderate priority issue. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N = 5.3) is internally consistent with the description: remote, unauthenticated, no user interaction, and impact limited to integrity (I:L) with no confidentiality or availability effect. The only impact is bypassing a deliberately-configured control - the plugin fails to honor the site's 'registration disabled' setting, letting anyone self-register and log in. SSVC confirms this profile: Exploitation 'none' (no observed active exploitation), Automatable 'yes' (a scriptable unauthenticated HTTP flow), Technical Impact 'partial'. A public POC exists (WPScan) and a vendor patch is available (3.7.50), but there is no EPSS score and no CISA KEV listing, so there is no evidence of active or widespread exploitation. Signals align rather than conflict: high CVSS reach (unauth/network) but modest real impact (unauthorized account creation at subscriber level only, which the site would otherwise have granted had registration been left on). Net: worth patching promptly on sites that intentionally disabled registration, but not an emergency; the 'partial' technical impact and absence of KEV/EPSS argue against panic. Note the CPE vendor is recorded as 'unknown' - the real vendor is StyleMixThemes.

Exploit ScenarioDerived

An attacker targets a WordPress site running MasterStudy LMS where the administrator has deliberately turned off open registration. Using the plugin's front-end registration endpoint, the attacker submits a registration request; because the plugin never checks the site's registration-enabled setting, an account is created and the attacker is automatically logged in. A public exploit is available via WPScan, and because the flow is unauthenticated and scriptable (SSVC Automatable: yes), it can be automated to mass-create accounts.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 24, 2026

Unauthenticated account creation in the MasterStudy LMS WordPress plugin (versions 2.3.0 through before 3.7.50) lets remote attackers create user accounts - and be logged into them - on WordPress sites where the administrator has deliberately disabled user registration. The plugin's front-end registration flow fails to consult the site's registration setting before creating the account (CWE-862, missing authorization), so the restriction the administrator put in place is simply not enforced; publicly available exploit code exists, though there is no confirmation of active exploitation (no CISA KEV listing, and CISA's SSVC assessment records exploitation as 'none'). Exploitation is unauthenticated and needs no user interaction (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N), but the impact is capped at subscriber-level account creation with no confidentiality or availability effect, making this a genuine but low-to-moderate priority issue.

RemediationAI

Vendor-released patch: upgrade the MasterStudy LMS WordPress plugin to 3.7.50 or later, which restores the missing registration-enabled authorization check; this is the primary fix and the only one that fully removes the flaw. If immediate upgrade is not possible, the most effective compensating control is to deactivate the plugin entirely (eliminating the unauthenticated registration route, at the cost of losing all LMS functionality), or - if the plugin must stay active - remove or unpublish the front-end registration pages/shortcodes it exposes and block requests to the plugin's registration endpoint at the WAF or reverse-proxy layer (this preserves LMS features but requires identifying and maintaining the endpoint pattern, and may break legitimate enrollment flows). Note that keeping WordPress registration enabled does not mitigate anything, since the exposed behavior is only meaningful where registration was disabled. Adding CAPTCHA or email verification to the flow reduces automated abuse volume but does not close the authorization bypass, and account-creation auditing/alerting only detects rather than prevents it. Confirm the applied version after patching and verify that account-creation attempts against the plugin's front-end flow now fail on registration-disabled sites; references: https://wpscan.com/vulnerability/57b0dd3f-bd83-4fb7-b98d-c999026910cd/ and https://nvd.nist.gov/vuln/detail/CVE-2026-88846.

Affected VersionsENISA

MasterStudy LMS WordPress Plugin 2.3.0 <3.7.50

Affected Packages

euvd masterstudy_lms_wordpress_plugin fix: 3.7.50

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

The affected component is the MasterStudy LMS WordPress plugin (CPE: cpe:2.3:a:unknown:masterstudy_lms_wordpress_plugin:*:*:*:*:*:*:*:*, with vendor recorded as 'unknown' in the supplied CPE data), a learning-management extension that ships its own front-end registration/onboarding flow separate from WordPress core's registration handler. The root cause is CWE-862 (Missing Authorization): the plugin's account-creation routine does not check the WordPress 'users_can_register' option (or an equivalent site-level registration policy) before calling its user-creation and session-establishment logic. As a result, a request to the plugin's registration endpoint succeeds even on sites where the administrator has intentionally turned registration off, and the response establishes an authenticated session for the newly created account. This is an authorization-logic flaw, not an injection or memory-safety issue, so the security consequence is limited to bypassing the site's registration policy; there is no direct data exposure or denial-of-service component. Because the crafted request is a plain unauthenticated HTTP call to a predictable plugin route, the issue is fully automatable (CISA SSVC: Automatable=yes, Technical Impact=partial).

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Severity by source

Vendor (WPScan) PRIMARY 5.3 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
vuln.today AI 5.3 MEDIUM

Unauthenticated network HTTP registration flow (AV:N/AC:L/PR:N/UI:N); impact limited to bypassing the registration policy (I:L) with no data exposure or downtime (C:N/A:N).

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

Primary rating from Vendor (WPScan).

CVSS VectorVendor: WPScan

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

Lifecycle Timeline

4
CVSS changed
Sep 24, 2026 - 11:22 NVD
5.3 (None) 5.3 (MEDIUM)
Patch available
Sep 24, 2026 - 07:01 EUVD
CVE Published
Sep 24, 2026 - 06:00 cve.org
MEDIUM 5.3
CVE Published
Sep 24, 2026 - 06:00 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

The MasterStudy LMS WordPress Plugin WordPress plugin before 3.7.50 does not check whether user registration is enabled on the site before creating an account through one of its front-end registration flows, allowing unauthenticated users to create accounts, and be logged into them, on sites where registration has been deliberately disabled.

Threat Intelligence Overview

EPSS Score
0.1%
Top 98% exploitable
Prevalence
Medium
popular WordPress LMS plugin, ~100k+ installs, common but not ubiquitous
Exploit
POC
Public exploit code exists
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 MEDIUM
CISA KEV No
Public POC Yes
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
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· derived
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

46
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +26
PoC: +20
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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CVE-2026-81197 MEDIUM POC
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Unauthenticated information disclosure in MasterStudy LMS WordPress Plugin before 3.7.46 exposes the titles and IDs of a

CVE-2026-81195 MEDIUM POC
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Unauthenticated information disclosure in MasterStudy LMS WordPress Plugin (all versions before 3.7.46) exposes per-stud

CVE-2026-81199 MEDIUM POC
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Unauthenticated information disclosure in MasterStudy LMS WordPress Plugin before 3.7.46 exposes learning statistics for

CVE-2026-81026 MEDIUM POC
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Payment verification bypass in MasterStudy LMS WordPress Plugin before 3.7.40 permits unauthenticated attackers to fraud

CVE-2026-81342 MEDIUM POC
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Open redirect in MasterStudy LMS WordPress Plugin before version 3.7.43 enables unauthenticated attackers to supply an u

CVE-2026-88847 MEDIUM POC
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Missing authorization checks in the MasterStudy LMS WordPress plugin before 3.7.50 let any authenticated user - includin

CVE-2026-88845 MEDIUM POC
4.3 Sep 24

Any authenticated WordPress user - down to the lowest-privilege Subscriber role - can invoke an administrative maintenan

CVE-2026-81194 MEDIUM POC
4.3 Sep 02

Broken object-level authorization in MasterStudy LMS WordPress Plugin before 3.7.46 exposes course sales records of any

CVE-2026-81198 LOW POC
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Cross-instructor content tampering in MasterStudy LMS WordPress Plugin before 3.7.46 allows authenticated instructor-rol

CVE-2026-81340 LOW POC
3.8 Sep 18

Broken object-level authorization in the MasterStudy LMS WordPress plugin before 3.7.50 lets an authenticated user holdi

CVE-2026-81196 LOW POC
2.7 Sep 02

Instructors in MasterStudy LMS WordPress Plugin versions before 3.7.46 can read quiz questions, correct answers, and exp

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