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Passster CVE-2025-15490

| EUVDEUVD-2025-210832 MEDIUM
Incorrect Authorization (CWE-863)
2026-09-02 WPScan GHSA-r64m-vg32-6jh4
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
    Fingerprint WordPress site for Passster plugin
  2. Exploit
    Craft URL bypassing global protection check
  3. Impact
    Access password-protected content without credentials

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

The Passster WordPress plugin must be installed, active, and configured to use its global protection feature to restrict access to site content. The bypass is triggered via crafted URLs targeting the plugin's protection-check logic - sites that do not use global protection mode (i.e., only apply per-page/per-post password protection through other mechanisms) may not be exposed to this specific bypass. No authentication is required (confirmed by PR:N in CVSS). Exploitation is further limited in impact to the content Passster was configured to protect; it does not grant WordPress admin access, database access, or the ability to modify content.

Impact

The CVSS 5.3 Medium score (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N) accurately captures the technical severity but underrepresents operational risk for sites that depend on Passster as their primary content-access control. The vulnerability is remotely exploitable with no authentication, no user interaction, and low attack complexity - all conditions that favor mass automated scanning. The C:L rating reflects that impact is scoped to plugin-protected content rather than full database or admin access, which is an important limiting factor. However, for deployments where Passster gates genuinely sensitive content (member-only material, internal documentation, unpublished drafts), the effective impact is far higher than C:L implies. A publicly available PoC lowers exploitation effort to near-zero. EPSS data was not provided, but the combination of AV:N/AC:L/PR:N and public PoC suggests meaningful real-world exploitation probability against actively targeted sites. No CISA KEV listing is present, indicating no confirmed broad exploitation campaign at time of analysis. Active exploitation is not confirmed.

Exploit ScenarioDerived

A publicly available PoC exists. An unauthenticated attacker identifies a WordPress site running a vulnerable Passster version through passive recon or automated plugin-fingerprinting, then sends a crafted URL that manipulates the plugin's global protection check - gaining read access to content intended to be locked behind a password gate without supplying any credentials.

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

Global protection bypass in the Passster WordPress plugin (versions before 4.2.26) allows unauthenticated remote attackers to access password-protected content by submitting crafted URLs that circumvent the plugin's site-wide protection checks. Because Passster's entire purpose is content gating, this vulnerability entirely nullifies the plugin's security guarantee for affected sites. A publicly available PoC exists, reported by WPScan, making automated scanning and exploitation straightforward.

RemediationAI

Update the Passster WordPress plugin to version 4.2.26 or later, which addresses the global protection bypass. The fix is documented in the WPScan advisory at https://wpscan.com/vulnerability/87d4768e-48a5-4d91-a5e1-8a84ba2de035/. For sites that cannot immediately update, implement server-level access controls as compensating measures: restrict access to protected WordPress routes via HTTP Basic Authentication configured in the web server (e.g., .htaccess on Apache or auth_basic in nginx) or apply IP allowlisting for sensitive content areas. Note that these workarounds require web server access and may affect legitimate users who access content from variable IP addresses. Disabling the global protection feature entirely removes the bypass surface but also removes all content protection, which is only acceptable as a temporary measure while patching.

Affected VersionsENISA

Passster 0 <4.2.26

Affected Packages

euvd passster fix: 4.2.26

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 restrict access to pages, posts, or entire sites behind password gates - its core function is access control for WordPress content. The vulnerability resides in the plugin's 'global protection' enforcement logic, which evaluates incoming requests to determine whether access should be granted or denied. The flaw appears to involve insufficient or bypassable URL-based checks, allowing a specially crafted URL to satisfy or skip the protection condition without providing valid credentials. The CWE is listed as N/A in available data; conceptually this aligns with CWE-288 (Authentication Bypass Using an Alternate Path) or CWE-807 (Reliance on Untrusted Inputs in a Security Decision). The CPE cpe:2.3:a:unknown:passster:*:*:*:*:*:*:*:* covers all versions before 4.2.26, with 'unknown' used as a vendor placeholder - a common NVD data gap for small WordPress plugins.

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  • Exploit and PoC references, threat intelligence from 22 sources

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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

Fully remote unauthenticated URL-based bypass; C:L reflects access to plugin-protected pages only, not admin, database, or file system access.

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 4.2.26 has a flaw in its global protection checks, allowing unauthenticated users to bypass the protection offered via crafted URLs

Threat Intelligence Overview

EPSS Score
0.2%
Top 89% exploitable
Prevalence
Low
niche WordPress content-protection plugin, limited deployment 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-2025-15489 MEDIUM POC
5.3 Sep 02

Unauthenticated information disclosure in the Passster WordPress plugin (versions before 4.2.24) allows remote attackers

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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