Sender Policy Bypass Enables Unauthorized Local File Disclosure

OpenClaw versions 2026.4.9 before 2026.4.10 contain a sender policy bypass vulnerability in the outbound host-media attachment read helper that allows unauthorized local file disclosure. Attackers with denied read access via toolsBySender or group policy can trigger host-media attachment loading to bypass sender and group-scoped authorization boundaries and retrieve readable local files through the outbound media path.

Casky was already ahead

This CVE exploits attack patterns that Casky's 261matched 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

OpenClaw versions 2026.4.9 and earlier contain a critical authorization bypass vulnerability in their outbound host-media attachment handler. The flaw allows attackers with denied read access—even those restricted by sender policies or group-scoped authorization controls—to circumvent these security boundaries and access readable files on the local system. This vulnerability is particularly concerning because it transforms a denied access state into an exploitable condition, affecting any organization using vulnerable OpenClaw deployments where file access controls are relied upon for data protection. The CVSS score of 7.7 reflects the high severity of unauthorized local file disclosure combined with the ease of exploitation for users already authenticated to the system.

Casky's 261 matching skills leverage Claude AI's extended reasoning to detect the attack patterns associated with this vulnerability across MITRE ATT&CK's Privilege Escalation (TA0004) and Credential Access (TA0006) tactics. Practitioners using Casky would identify suspicious patterns including: unusual host-media attachment loading requests originating from accounts with explicitly denied toolsBySender or group policy restrictions; outbound media path access attempts that bypass expected authorization checks; and file read operations on sensitive local resources occurring outside normal workflows. The platform's skill set helps security teams recognize the authorization boundary violations characteristic of CWE-863 (Improper Authorization) and correlate these indicators with potential lateral movement or data exfiltration attempts, enabling faster detection and containment before sensitive data is disclosed.

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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 →

261 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-42438.

analyzing-cloud-storage-access-patterns

cloud security · low

Run

analyzing-kubernetes-audit-logs

container security · low

Run

analyzing-malicious-url-with-urlscan

phishing defense · medium

Run

MITRE ATT&CK Techniques

TA0004 TA0006

Investigate the attack patterns behind CVE-2026-42438

Casky has 261 skills that investigate the attack patterns behind CVE-2026-42438. Run one and get CVSS-scored findings in 3 minutes.

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