Eclipse Milo Batch Authorization Bypass in OPC UA

In Eclipse Milo versions 1.0.0 through 1.1.4, the Call service dispatches the original mixed batch to address-space handlers after calculating authorization, allowing an anonymous or otherwise low-privileged client to execute a denied method by batching it with an allowed method.

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

Eclipse Milo versions 1.0.0 through 1.1.4 contain a critical authorization flaw in the Call service where batch requests bypass permission checks. The vulnerability allows low-privileged or anonymous clients to execute denied methods by combining them with authorized methods in a single batch request. The service calculates authorization once for the batch but then dispatches the original unfiltered request to address-space handlers, enabling privilege escalation. This affects organizations using Milo for OPC UA implementations in industrial control systems, manufacturing environments, and critical infrastructure where method execution should be strictly controlled.

Casky's 283 matching skills leverage Claude's extended reasoning to detect the attack patterns mapped to MITRE TA0004 (Privilege Escalation) and TA0006 (Credential Access). Practitioners using Casky would observe findings highlighting suspicious batch Call requests that contain a mix of authorized and unauthorized methods, detection of repeated failed method calls followed by batched requests, and anomalous service invocations from low-privilege accounts attempting to execute sensitive operations. The platform's skills identify the authorization check bypass pattern by correlating the timing of permission validation against actual method execution, surfacing the discrepancy that indicates a batching attack. Security teams would see alerts on OPC UA Call service abuse, privilege boundary violations, and unauthorized address-space modifications—enabling rapid response before attackers manipulate critical industrial processes.

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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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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-2026-62927.

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-2026-62927

Casky has 283 skills that investigate the attack patterns behind CVE-2026-62927. Run one and get CVSS-scored findings in 3 minutes.

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