Unauthenticated File Upload Bypass in WordPress User Profile Builder

The User Profile Builder WordPress plugin before 4.0.1 does not properly restrict its front-end file upload feature, granting unauthenticated visitors capabilities reserved to privileged roles. This allows them to list the site's media library and to modify unpublished posts, pages and media items belonging to other users.

Casky was already ahead

This CVE exploits attack patterns that Casky's 283matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

The User Profile Builder WordPress plugin before version 4.0.1 contains a critical authentication bypass vulnerability that exposes sites to unauthorized access and data manipulation. By failing to properly validate user permissions on its front-end file upload feature, the plugin allows unauthenticated visitors to perform actions typically restricted to administrators and editors—specifically listing media libraries and modifying other users' unpublished content. This CWE-287 (Improper Authentication) flaw affects any WordPress installation running the vulnerable plugin version, with particular risk for multi-author sites where content sensitivity varies. The CVSS 8.2 rating reflects the high impact of unauthorized information disclosure and content tampering without requiring valid credentials or user interaction.

Casky's 283 mapped security skills leverage Claude's extended reasoning to detect the attack patterns underlying this vulnerability across MITRE ATT&CK tactics TA0004 (Privilege Escalation) and TA0006 (Credential Access). Practitioners using Casky would identify suspicious indicators such as unauthenticated HTTP requests to plugin upload endpoints that succeed without valid nonce tokens or capability checks, anomalous media library enumeration from external IPs, and modification timestamps on unpublished posts originating from unauthenticated sessions. The platform's skill set would flag these behavioral patterns—particularly privilege escalation via missing authorization controls and unauthorized data access—correlating them to the specific plugin behavior to enable rapid detection and response before exploitation occurs.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

283 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-76548.

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

Access with Stolen Session Cookie

identity access management · low

Run

MITRE ATT&CK Techniques

TA0004 TA0006

Investigate the attack patterns behind CVE-2026-76548

Casky has 283 skills that investigate the attack patterns behind CVE-2026-76548. Run one and get CVSS-scored findings in 3 minutes.

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