Prisma Browser EUVD-2026-30089

Attacker must already have an interactive, logged-in non-admin local account (or code execution in such a user's session) on a macOS host that has Palo Alto Networks Prisma Browser installed at a version below 146.16.6.165, and the Prisma Browser application must be running or launchable so its Apple Event handler is reachable. The exploit specifically requires the macOS AppleScript / Apple Events IPC path - it does not apply to Prisma Browser on Windows or to headless deployments. Limiting factors: no network-only path (CVSS AV:L), PR:L means an unauthenticated remote attacker cannot reach this directly, and AT:P indicates a specific technique/condition (the exposed Apple Event handler) is needed; user interaction is not required (UI:N), and impact is scoped to the browser process rather than the underlying OS (SC:N/SI:N/SA:N).

The CVSS 4.0 vector (AV:L/AC:L/AT:P/PR:L/UI:N, VC:H/VI:H/VA:L) describes a local, low-complexity attack that requires some pre-existing privilege (a logged-in non-admin account) and a specific attack template (the Apple Event handler must be reachable), with high confidentiality and integrity impact on the browser and only low availability impact - consistent with browser-context command execution rather than full host takeover. Real-world risk signals are mixed: EPSS is essentially zero (0.02%, 6th percentile) and SSVC marks Exploitation as 'none' and Automatable as 'no', meaning CISA's framework currently treats this as not-yet-exploited and not mass-exploitable; however, SSVC Technical Impact is 'total', and the vendor itself filed the advisory, so the bug is real and material on managed macOS fleets. This is a meaningful but not emergency-tier issue - prioritize it on endpoints where Prisma Browser is the policy-enforcing browser for sensitive sessions, and treat it as standard patch-cycle work elsewhere. One caveat: SSVC 'Exploitation: none' and the absence of KEV are point-in-time signals, so monitor for change.

On a shared or compromised macOS endpoint, a low-privileged local user (or malware running in their context - e.g., delivered via a phishing payload that does not need admin rights) runs a small AppleScript such as tell application "Prisma Browser" to ... to drive the browser through its unrestricted Apple Event handler. They use this to issue commands as the targeted browser user - navigating to attacker-controlled URLs, exfiltrating session data, or triggering authenticated actions in already-logged-in tenant apps. No public exploit identified at time of analysis, but AppleScript-based abuse of misconfigured Apple Event handlers is well-understood and trivially scriptable once the handler surface is known.