CVE-2026-17559: CWE-863 Incorrect Authorization in Passster
Description
CVE-2026-17559 is a medium severity vulnerability in the Passster WordPress plugin versions 4.3.3 up to but not including 4.3.9. The plugin incorrectly authorizes REST API requests by matching endpoint paths as unanchored substrings rather than resolved routes. This flaw allows unauthenticated attackers to bypass global password protection and read protected post and page content.
CVSS v3.1
Score 5.3medium
Affected software
Passster
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Passster WordPress plugin before version 4.3.9 contains an authorization flaw (CWE-863) where it improperly matches its own public endpoint paths against REST API request URIs. Instead of matching against the fully resolved route, it uses an unanchored substring comparison. This incorrect authorization check permits unauthenticated attackers to access content that should be protected by a global password, specifically allowing them to read posts and pages that are globally password-protected.
Potential Impact
An unauthenticated attacker can bypass the global password protection mechanism of the Passster plugin and read the content of posts and pages that are intended to be protected. This leads to unauthorized disclosure of potentially sensitive information. The vulnerability does not affect integrity or availability, only confidentiality.
Mitigation Recommendations
Upgrade the Passster plugin to version 4.3.9 or later, where this authorization issue has been fixed. Since the vulnerability affects versions >=4.3.3 and <4.3.9, applying the official update fully mitigates the risk. No other mitigation is indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- WPScan
- Date Reserved
- 2026-07-27T13:36:40.825Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a883c15acd9273b4916aa2d
Added to database: 08/21/2026, 11:52:53 UTC
Last enriched: 09/11/2026, 02:48:48 UTC
Last updated: 10/05/2026, 18:48:17 UTC
Views: 86
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.