Samba Daemon Privilege Escalation via Misconfigured File ACLs

OpenWrt luci-app-samba4 read ACL grants file.exec permission on /usr/sbin/smbd, allowing authenticated delegated users to execute the Samba daemon with caller-controlled command-line arguments. Attackers can pass arbitrary Samba global options such as message command to a root smbd process, triggering command execution when SMB protocol messages are processed.

Casky was already ahead

This CVE exploits attack patterns that Casky's 224matched 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-2026-59260 exploits a critical access control misconfiguration in OpenWrt's luci-app-samba4 where the Samba daemon executable (/usr/sbin/smbd) is granted executable permissions to authenticated delegated users. This vulnerability enables privilege escalation because attackers can invoke the smbd process as root while injecting arbitrary command-line arguments, particularly dangerous Samba global options like "message command" that execute system commands during SMB protocol message handling. OpenWrt users running Samba shares with delegated authentication are directly at risk, as are any networked systems relying on these deployments for file sharing. The CVSS 8.8 rating reflects the severity: an authenticated attacker gains code execution with root privileges, providing complete system compromise.

Casky's 224 mapped security skills leverage Claude's extended reasoning to identify the attack chain underlying this vulnerability across MITRE ATT&CK's Privilege Escalation (TA0004) and related techniques. Practitioners using Casky would observe findings highlighting suspicious smbd process invocations with non-standard arguments, unexpected command-line injections targeting global Samba options, and authentication-to-execution patterns where delegated users trigger root-level processes. The platform's skill mapping helps detect the specific indicator: file permission anomalies on system binaries combined with authenticated access patterns, followed by arbitrary command injection attempts. This multi-layered detection approach catches both the misconfiguration allowing execution and the exploitation attempts leveraging caller-controlled arguments to achieve arbitrary code execution.

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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 →

224 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-59260.

abusing-dpapi-for-credential-access

red teaming · high

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abusing-shadow-credentials-for-privesc

red teaming · high

Run

Access with Stolen Session Cookie

penetration testing · medium

Run

MITRE ATT&CK Techniques

TA0004

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Casky has 224 skills that investigate the attack patterns behind CVE-2026-59260. Run one and get CVSS-scored findings in 3 minutes.

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