VMware Fusion TOCTOU Privilege Escalation via SETUID Binary

VMware Fusion contains a TOCTOU (Time-of-check Time-of-use) vulnerability that occurs during an operation performed by a SETUID binary. A malicious actor with local non-administrative user privileges may exploit this vulnerability to escalate privileges to root on the system where Fusion is installed.

Casky was already ahead

This CVE exploits attack patterns that Casky's 203matched 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

CVE-2026-41702 represents a Time-of-Check Time-of-Use (TOCTOU) race condition in VMware Fusion's SETUID binary operations. This vulnerability allows a local attacker with non-administrative privileges to escalate to root access by exploiting the window between when the system checks file permissions and when it actually uses the file. TOCTOU vulnerabilities are particularly dangerous because they require minimal user interaction and can be triggered repeatedly until the race condition succeeds. This affects any system with VMware Fusion installed, putting macOS and Linux users at risk of complete system compromise through local privilege escalation.

Casky.ai's 203 mapped security skills leverage Claude's extended reasoning to detect the attack patterns associated with TA0004 (Privilege Escalation) techniques by analyzing behavioral indicators of TOCTOU exploitation attempts. Practitioners using the platform would observe detections for suspicious SETUID binary interactions, rapid successive file access patterns on system-critical files, and temporal anomalies in permission checks versus file operations. The skills specifically flag attempts to manipulate symbolic links or file descriptors between check and use operations, monitor for repeated execution attempts that characterize race condition exploitation, and correlate process behavior with file system metadata changes. This multi-dimensional analysis helps security teams identify exploitation attempts in real-time, enabling rapid response before privilege escalation completes.

Live Threat IntelligenceComing soon

Casky Risk Score

—

EPSS Probability

—

Shodan Exposure

—

GreyNoise Signal

—

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 →

203 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-41702.

analyzing-cloud-storage-access-patterns

cloud security · low

Run

analyzing-kubernetes-audit-logs

container security · low

Run

analyzing-office365-audit-logs-for-compromise

cloud security · low

Run

MITRE ATT&CK Techniques

TA0004

Investigate the attack patterns behind CVE-2026-41702

Casky has 203 skills that investigate the attack patterns behind CVE-2026-41702. Run one and get CVSS-scored findings in 3 minutes.

Run the skill that detects this →

X Instagram LinkedIn