ClearanceKit EUVD-2026-46113

Exploitation requires a process running as root on the target macOS system (PR:H, confirmed by CVSS vector). ClearanceKit must be installed and its system extension active, with the vulnerable ECDSA signing key already persisted in the macOS legacy System Keychain - a condition met by any deployment of versions prior to 5.0.10. The specific attack requirement (AT:P) is the macOS legacy System Keychain behavior that silently ignores kSecAttrAccess for kSecClassKey items; this is a platform-intrinsic condition present on all affected macOS versions where ClearanceKit runs. Access is local-only (AV:L); remote exploitation is not possible without a separate independent path to root. No user interaction is required once root is obtained (UI:N). The key limiting factor is the root prerequisite: this vulnerability does not enable privilege escalation to root and cannot be exploited from lower privilege levels. Exploitation is further limited to macOS environments where ClearanceKit is the active policy enforcement mechanism.

The CVSS 4.0 score of 6.9 (vector AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N) accurately reflects a constrained but non-trivial risk profile. Local attack vector (AV:L) and high privilege requirement (PR:H) confirm that exploitation demands an already-rooted macOS system, meaning this vulnerability cannot be used for initial access or privilege escalation to root - it requires root as a prerequisite. AT:P indicates specific attack requirements: the macOS legacy System Keychain's kSecClassKey ACL-silencing behavior must be present, which is inherent to the platform on affected deployments. The subsequent system integrity and confidentiality impacts (SC:H/SI:H) are significant: a root attacker can silently replace the enforced access policy with arbitrary content, undermining the entire security guarantee ClearanceKit provides to the deployment. No CISA KEV listing and no public exploit are identified; EPSS data was not provided, so exploitation probability cannot be quantified. For organizations that have deployed ClearanceKit as a compensating control or compliance measure, the ability of any root process to silently subvert its policy enforcement is a critical trust-integrity failure, even if the raw CVSS score appears moderate. The constraint is real: this is not exploitable without root, making it a chaining vulnerability in attack scenarios rather than a standalone threat.

An attacker with established root access on a macOS system running ClearanceKit prior to 5.0.10 retrieves the ECDSA private key directly from the System Keychain using standard Security framework APIs - no ACL challenge is raised because the key's access restriction was silently discarded when first persisted. The attacker signs a crafted policy database that whitelists unrestricted file-system access for a chosen malicious process, then replaces /Library/Application Support/clearancekit/store.db with the forged file; ClearanceKit validates the signature, accepts the database as authoritative, and begins enforcing attacker-defined policies transparently. No public exploit code is known, but the technique is operationally straightforward for any attacker already holding root with knowledge of macOS Security framework APIs.