Fleet CVE-2026-111923

Exploitation requires the Fleet server to have Apple MDM enrollment configured and its enrollment endpoints network-reachable by the attacker; these endpoints are unauthenticated by design to allow device enrollment, so no credentials or user interaction are needed (consistent with PR:N/UI:N). The key limiting factor is deployment mode: Fleet instances that do not have Apple MDM enabled, or that restrict enrollment-endpoint network exposure, are not exposed to this attack. Impact is confined to availability (server crash/resource exhaustion) - there is no path to data access or code execution.

This is a genuine operational priority for anyone running Fleet with Apple MDM enabled, though it is availability-only - not a confidentiality or code-execution issue. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N) describes the worst case for a DoS: network-reachable, low complexity, no authentication, no user interaction, with high availability impact (VA:H) and zero confidentiality/integrity impact (VC:N/VI:N). The ~150-byte amplification described (a tiny crafted binary plist causing exponential allocation/infinite recursion, CWE-674) makes this trivially weaponizable and cheap to repeat, so the technical-impact and automatable characteristics skew toward easy, repeatable exploitation. However, no EPSS score, no CISA KEV listing, and no public POC are present in the provided data, so there is no evidence of active exploitation - the signals here are entirely structural (vector + description) rather than observed. Net: treat as a high-priority patch for Fleet operators exposing MDM enrollment to untrusted networks, but recognize this is a service-crash risk, not data compromise. Note the single conflicting-context caveat: exploitability depends on the Apple MDM enrollment endpoints actually being enabled/reachable, which the raw PR:N does not capture.

An unauthenticated attacker who can reach a Fleet server's Apple MDM enrollment endpoint sends a crafted ~150-byte binary property list that triggers unbounded recursion or exponential allocation during parsing. The parser exhausts CPU and memory, crashing or hanging the server and denying MDM service to legitimate devices. No public exploit code is identified at time of analysis, but the payload is small and the trigger is described in detail, making reliable reproduction straightforward.