New macOS XPC Security Flaw Lets Standard Users Disable Enterprise Defenses

A newly discovered macOS security flaw allows attackers with standard user accounts to disable enterprise-grade endpoint protection tools without requiring administrator privileges. Security research firm XM Cyber identified a technique exploiting Apple's XPC communication framework, successfully bypassing defenses in widely used platforms like CrowdStrike Falcon and Kandji.

The vulnerability centers on how macOS applications verify requests sent to privileged background services. Attackers who gain initial access to a standard user account can modify parts of a legitimate, signed application bundle with a malicious payload. Because macOS caches the application's trust fingerprint upon launch, the modified payload inherits this trust, allowing it to invoke privileged XPC methods.

This chain of calls enabled researchers to unload the CrowdStrike Falcon security sensor and deactivate Kandji's uninstall protections. Notably, neither demonstration required a kernel exploit or bypassing System Integrity Protection (SIP), making the attack highly effective once local access is achieved.

Since the attack requires initial local access to a target Mac, organizations must prioritize securing standard user accounts to prevent the exploit chain from beginning.

• Update endpoint management software immediately; Kandji has already patched the vulnerability and assigned it CVE-2026-39118.
• Enforce strict multi-factor authentication (MFA) and strong password policies to prevent the initial account compromise required for this exploit.
• Monitor vendor advisories closely, as Apple has not yet issued an independent security advisory or OS-level patch for this specific XPC trust caching behavior.

This discovery exposes a fundamental flaw in how enterprise Mac deployments handle internal application trust. By relying primarily on code-signing checks rather than continuously verifying the integrity of the caller, developers have inadvertently turned Apple's XPC framework into a viable attack surface.

While Kandji's swift patching of CVE-2026-39118 is a positive step, the broader implication is that any macOS security tool relying on cached trust fingerprints remains potentially vulnerable. As Macs continue to capture a larger share of the enterprise market, security vendors will be forced to overhaul their XPC validation protocols before XM Cyber releases its open-source XPC Hunter tool at the upcoming Black Hat Arsenal in August.