EUVD-2026-41001
GHSA-fmmf-42mh-hr4x
Severity by source
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:C/RE:L/U:Amber
TOCTOU race requires timing precision warranting AC:H; local low-privileged access (AV:L/PR:L); root escalation from a non-root process constitutes a scope change (S:C) with full CIA impact.
Primary rating from Vendor (Cato).
CVSS VectorVendor: Cato
Lifecycle Timeline
3DescriptionCVE.org
Improper certificate validation and a time-of-check time-of-use (TOCTOU) race condition in the PrivilegedHelperTool XPC service in Cato Client before v.5.13.1 on macOS allows a local authenticated attacker to escalate privileges to root via a self-signed certificate that bypasses the XPC caller verification and a symlink swap during package installation.
AnalysisAI
Local privilege escalation in Cato Client on macOS allows an authenticated low-privileged user to gain root by chaining two flaws in the PrivilegedHelperTool XPC service: improper certificate validation (CWE-295) that accepts self-signed certificates to bypass XPC caller verification, and a TOCTOU race condition exploitable via symlink swap during package installation. All Cato Client (SDP Client) versions prior to 5.13.1 on macOS are affected. A proof-of-concept exists per the CVSS 4.0 supplemental metric E:P, and the AU:Y (Automatable) tag indicates the exploit chain can be scripted - elevating practical urgency despite the absence of a CISA KEV listing.
Technical ContextAI
Cato Client (CPE: cpe:2.3:a:cato_networks:sdp_client:*:*:*:*:*:*:*:*) is the macOS endpoint agent for Cato Networks' SASE/SDP platform. On macOS, privileged operations are delegated to a PrivilegedHelperTool, a background daemon communicating with the main process via Apple's XPC inter-process communication framework, which is intended to enforce code-signing and entitlement checks on callers. CWE-295 (Improper Certificate Validation) describes the root cause: the XPC service does not properly verify that caller certificates are issued by a trusted authority, permitting self-signed certificates to satisfy XPC caller verification and bypass privilege separation. This is compounded by a TOCTOU (Time-of-Check Time-of-Use) race condition during package installation: the privileged helper checks a file target at one moment, but an attacker can atomically swap a symlink before the privileged write or execution occurs, redirecting the operation to an attacker-controlled path. The combination undermines both authentication of XPC callers and the integrity of installation-time file operations.
RemediationAI
Upgrade Cato Client to version 5.13.1 or later immediately; this is the vendor-confirmed patched release, documented in the Cato Networks advisory at https://support.catonetworks.com/hc/en-us/articles/37284626576413. If immediate upgrade is operationally blocked, restrict local interactive access on macOS endpoints to fully trusted users only - the attack requires an authenticated low-privileged local session, so limiting who can log in locally reduces exposure, though it may impact legitimate remote work scenarios. As a detection-oriented compensating control, enable macOS Endpoint Security framework logging for XPC service calls from PrivilegedHelperTool and monitor for unexpected symlink creation or swap operations in the Cato Client installation directory during installation events; this will not prevent exploitation but may surface attempts. Note that neither workaround eliminates the underlying certificate validation or TOCTOU flaw - patching to 5.13.1 is the only complete remediation.
Same weakness CWE-295 – Improper Certificate Validation
View allSame technique Authentication Bypass
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External POC / Exploit Code
Leaving vuln.today