WordPress FIFU Plugin REST API NONCE Bypass

The Featured Image from URL (FIFU) WordPress plugin before 6.0.8, Featured Image from URL (FIFU) Premium WordPress plugin before 8.2.8 do not correctly enforce the REST API nonce, disabling the check for the whole request when a crafted URL is used, which could allow attackers to make a logged-in administrator perform any REST API action, such as creating a new administrator account, via a CSRF attack.

Casky was already ahead

This CVE exploits attack patterns that Casky's 323matched 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 Featured Image from URL (FIFU) WordPress plugin contains a critical cross-site request forgery (CSRF) vulnerability that disables REST API nonce validation when a specially crafted URL is provided. This affects both the free plugin (before 6.0.8) and premium version (before 8.2.8), impacting WordPress administrators who have installed either variant. Because nonce checks are bypassed for the entire request, attackers can trick logged-in administrators into performing unauthorized REST API actions, including creating new administrator accounts, modifying site content, or installing malicious plugins—effectively granting complete site compromise without additional authentication.

Casky's 323 mapped security skills leverage Claude's extended reasoning to detect this attack pattern by correlating indicators across MITRE ATT&CK techniques TA0001 (Initial Access) and TA0043 (Reconnaissance). Practitioners using Casky would observe detection of suspicious REST API calls lacking proper nonce validation, cross-origin requests to WordPress REST endpoints from unexpected referrers, and POST requests that create privileged accounts or modify core configurations without valid CSRF tokens. The platform's skill matrix would highlight the chain: crafted URL injection → nonce bypass → unauthorized administrative action, allowing security teams to identify both exploitation attempts and misconfigurations in plugin security posture before compromise 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 →

323 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-101147.

Abuse of Public-Facing API: Mobile API Abuse

mobile security · low

Run

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

MITRE ATT&CK Techniques

TA0001 TA0043

Investigate the attack patterns behind CVE-2026-101147

Casky has 323 skills that investigate the attack patterns behind CVE-2026-101147. Run one and get CVSS-scored findings in 3 minutes.

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