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Passster EUVDEUVD-2025-210831

| CVE-2025-15489 MEDIUM
Incorrect Authorization (CWE-863)
2026-09-02 WPScan GHSA-96qf-ff37-rrr4
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 WordPress site running Passster
  2. Delivery
    Send unauthenticated AJAX request to admin-ajax.php
  3. Exploit
    Trigger unguarded AJAX handler
  4. Execution
    Bypass password gate
  5. Impact
    Retrieve protected content value

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization logic validation
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

No special conditions - remote unauthenticated exploitation against any WordPress installation running Passster before version 4.2.24. The CVSS vector (AV:N/AC:L/PR:N/UI:N) confirms no authentication, no user interaction, and no unusual server configuration is required. The sole prerequisite is that the target site has the Passster plugin installed, active, and has at least one content item configured as password-protected (i.e., the feature is in use). Exploitation is limited to content values protected by Passster; broader system data, WordPress credentials, or data outside the plugin's scope are not exposed by this flaw alone.

Impact

The provided CVSS 5.3 Medium score (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N) is technically accurate in that only limited content data is disclosed rather than credentials or system data. However, context elevates real-world risk: the entire value proposition of Passster is content access control, and this flaw renders that control ineffective - for sites that rely on Passster to protect business-sensitive, subscription-gated, or restricted content, the business impact can substantially exceed what C:L implies. A public exploit from WPScan (a widely used, trusted vulnerability intelligence platform) further lowers the exploitation barrier to near-zero. EPSS data is not provided; however, the combination of zero prerequisites and a published PoC suggests meaningful near-term exploitation probability. No CISA KEV listing is noted at time of analysis. The flaw is not in CISA KEV and there are no SSVC signals indicating active exploitation, but the public PoC and trivial attack complexity make this a genuine patch-now priority for any site using the plugin.

Exploit ScenarioDerived

An unauthenticated attacker identifies a WordPress site running Passster before 4.2.24 - detectable via plugin enumeration or version disclosure in page source - and submits a crafted HTTP POST to the site's wp-admin/admin-ajax.php endpoint targeting the vulnerable AJAX action. The server, lacking authorization checks, returns the password-protected content value in the response, bypassing the intended password gate entirely. A public PoC from WPScan makes this repeatable with minimal attacker skill.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 02, 2026

Unauthenticated information disclosure in the Passster WordPress plugin (versions before 4.2.24) allows remote attackers to retrieve the values of password-protected content via an improperly handled AJAX action. Because Passster's sole function is gating content behind passwords, this flaw entirely negates its intended protection guarantee. A public exploit is available via WPScan, and the zero-prerequisite attack vector makes this trivially exploitable against any affected installation.

RemediationAI

Upgrade Passster to version 4.2.24 or later - this is the vendor-released patch that resolves the improper input handling in the vulnerable AJAX action. Site administrators should apply this update immediately given the availability of a public exploit. As a temporary compensating control, deactivating the Passster plugin entirely via the WordPress admin panel eliminates the vulnerable endpoint, though this also removes all password-protection functionality the plugin provides. No other server-side workaround (such as blocking specific AJAX actions via WAF rule) is a reliable substitute for patching, as the action name would need to be confirmed from the plugin source. The WPScan advisory at https://wpscan.com/vulnerability/b1b4f64a-5bff-486e-a3e5-e71b5ca28d78/ should be monitored for any further updates.

Affected VersionsENISA

Passster 0 <4.2.24

Affected Packages

euvd passster fix: 4.2.24

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

Passster is a WordPress plugin designed to protect page or post content behind a password gate. The vulnerability exists in a WordPress AJAX action (wp_ajax_nopriv_ handler, accessible to unauthenticated users) that does not properly validate or authorize the incoming request before returning the protected content value. No CWE is formally assigned, but the root cause maps to CWE-862 (Missing Authorization) - the handler exposes sensitive output without verifying the caller holds the password. The affected product is identified by CPE cpe:2.3:a:unknown:passster:*:*:*:*:*:*:*:*, where 'unknown' is a placeholder for the true vendor slug. The WPScan advisory at https://wpscan.com/vulnerability/b1b4f64a-5bff-486e-a3e5-e71b5ca28d78/ is the primary intelligence source and also carries the exploit reference.

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Severity by source

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

Network-reachable with no authentication or interaction required; only limited content value is disclosed with no integrity or availability impact.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/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
Low
Integrity
None
Availability
None

Lifecycle Timeline

2
Patch available
Sep 02, 2026 - 16:02 EUVD
CVE Published
Sep 02, 2026 - 14:25 cve.org
MEDIUM 5.3

DescriptionCVE.org

The Passster WordPress plugin before 4.2.24 does not handle input properly in an AJAX action, allowing unauthenticated users to retrieve the value of password protected content

Threat Intelligence Overview

EPSS Score
0.2%
Top 91% exploitable
Prevalence
Low
niche WordPress content-protection plugin, limited production footprint
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 0.2%
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
Poc
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.

CVE-2026-16604 HIGH POC
7.5 Aug 05

Password-protected block content in the Passster WordPress plugin (all versions before 4.3.6) is rendered into the publi

CVE-2026-16603 HIGH POC
7.5 Aug 05

Category-locked content in the Passster WordPress plugin (all versions before 4.3.6) is fully exposed through the native

CVE-2026-16602 HIGH POC
7.5 Aug 05

Unauthenticated content disclosure in the Passster WordPress plugin (versions before 4.3.6) allows any remote user to re

CVE-2022-3206 MEDIUM POC
5.9 Oct 17

The Passster WordPress plugin before 3.5.5.5.2 stores the password inside a cookie named "passster" using base64 encodin

CVE-2026-17559 MEDIUM POC
5.3 Aug 21

Passster WordPress plugin versions before 4.3.9 exposes globally password-protected post and page content to unauthentic

CVE-2025-15490 MEDIUM POC
5.3 Sep 02

Global protection bypass in the Passster WordPress plugin (versions before 4.2.26) allows unauthenticated remote attacke

CVE-2024-2026 MEDIUM
6.4 Apr 09

The Passster plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's content_protector shortc

CVE-2024-0616 MEDIUM
5.3 Feb 29

The Passster - Password Protect Pages and Content plugin for WordPress is vulnerable to Sensitive Information Exposure i

CVE-2026-110896 MEDIUM
5.3 Oct 16

Missing authorization in the WP Chill Passster WordPress plugin (content-protector) through version 4.3.18 allows unauth

CVE-2026-62114 MEDIUM
5.3 Sep 11

Broken access control in the Passster WordPress content-protection plugin (versions up to and including 4.3.13) allows u

CVE-2024-11282 MEDIUM
5.3 Jan 07

The Passster - Password Protect Pages and Content plugin for WordPress is vulnerable to Sensitive Information Exposure i

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