Apple macOS EUVD-2026-77877

Requires a malicious or compromised application to already be running locally on the macOS host with normal (non-root) user privileges (AV:L, PR:L, UI:N) - there is no remote or network exploitation path. The flaw lets that app circumvent the intended permission restrictions to access protected user data. Exploitation is limited to unpatched systems: macOS Sequoia before 15.8, macOS Tahoe before 26.7, and macOS Golden Gate before 27; the vulnerability is closed by Apple's 'additional restrictions' fix. Primary limiting factor is the local prerequisite - the attacker must first achieve local code execution (e.g., via a downloaded/sideloaded app), so this is best treated as a post-compromise data-access primitive rather than an initial-access vector.

This is a low-to-moderate priority issue despite its 5.5 (Medium) CVSS score. The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N) is internally consistent and confidentiality-only: an already-installed, low-privilege local app gains access to protected user data, with no integrity or availability impact. All exploitation signals point the same direction and reinforce low urgency: EPSS is 0.17% (6th percentile), there is no CISA KEV listing, and no public POC is referenced. The local attack vector (AV:L) is the dominant risk-limiting factor - this is not remotely reachable and requires code already running on the device. One labeling mismatch to note: the CWE is CWE-269 (Improper Privilege Management) and the tag reads 'Privilege Escalation,' but the vector shows confidentiality-only impact (C:H, I:N, A:N) with no scope change, so the real-world effect is unauthorized access to protected data rather than gaining elevated execution privileges - treat this as an information-disclosure/access-control flaw. No signals conflict with the CVSS local classification; the description ('An app may be able to access protected user data') aligns with AV:L/PR:L.

A user installs or is tricked into running a malicious or trojanized app on macOS. Because of the permissions flaw, that low-privilege app bypasses the intended access restrictions and reads protected user data (e.g., data normally gated behind TCC/permission prompts) without further authorization. No public exploit code is identified, and the attack requires the app to already be executing locally on the target Mac.