CVE-2026-34389

Fleet versions before 4.87.0 contain an authentication bypass vulnerability in the device API that accepts hostnames and hardware serials as authentication tokens in addition to device UUIDs. Unauthenticated attackers who know or guess these non-secret identifiers can authenticate as iOS/iPadOS hosts to read device data and trigger device-scoped actions including software installation and MDM migration.

In Fleet prior to version 4.81.0, metadata from software packages (.pkg, .deb, .rpm, .exe, .msi) is not properly sanitized before being included in generated uninstall scripts. A crafted package with malicious metadata values can cause arbitrary command execution as root (macOS/Linux) or SYSTEM (Windows) on managed endpoints when uninstall is triggered.

Fleet before 4.83.0 contains a denial of service vulnerability that allows unauthenticated attackers to exhaust server memory by sending gzip-compressed request bodies. Attackers can send small, highly compressed requests with Content-Encoding: gzip to unauthenticated endpoints that expand during decoding, crashing the entire Fleet instance.

Fleet before 4.89.0 contains an unbounded recursion vulnerability in Apple MDM enrollment property list parsing that allows unauthenticated attackers to crash the server. Attackers can send a crafted binary plist payload of about 150 bytes to the enrollment endpoints, triggering exponential allocation or infinite recursion that exhausts CPU and memory.

A vulnerability has been identified within Fleet where, by default, Fleet will automatically trust a remote server’s certificate when connecting through SSH if the certificate isn’t set in the `known_hosts` file. This could allow the execution of a man-in-the-middle (MitM) attack against Fleet. In case the server that is being connected to has a trusted entry in the known_hosts file, then Fleet will correctly check the authenticity of the presented certificate.

Fleet versions before 4.89.0 fail to properly filter MDM command results by team authorization in the commands/results endpoint. Team-scoped users can read MDM command results for hosts on other teams when a shared command UUID targets hosts across multiple teams, exposing host UUIDs, command payloads, and device responses.

Fleet before 4.87.0 does not protect the two endpoints that serve in-house iOS application packages and manifests (enterprise tier only) with the intended random, time-limited URL token. Because Apple's InstallEnterpriseApplication MDM command requires these URLs to be reachable without a Fleet session, they cannot rely on session-based authentication, and the missing token allows an unauthenticated attacker with network access to the Fleet server to download in-house IPA binaries and their metadata by guessing sequential title identifiers. The impact is limited to read-only disclosure; there is no privilege escalation or write access, and the free tier is unaffected.

Fleet before 4.89.0 contains an SQL injection vulnerability in the activity list endpoints (GET /api/v1/fleet/activities and GET /api/v1/fleet/hosts/{id}/activities). The deprecated cursor-pagination helper interpolated the sort/order key into the SQL ORDER BY clause without an allowlist, allowing authenticated users with read access to order results by arbitrary columns. Impact is read-only and bounded to columns on the activity_past table not otherwise returned.

Fleet-maintained app install and uninstall scripts for macOS are generated from Homebrew cask metadata. In manifests generated before 2026-08-19, the script generator escaped this metadata at some interpolation sites but not all, allowing cask metadata containing shell metacharacters to be carried into scripts that execute as root. An attacker who could land crafted metadata in an upstream Homebrew cask could achieve arbitrary command execution as root on managed macOS hosts.

A security vulnerability was discovered in Fleet's Helm template preprocessing where templates evaluated by the Fleet controller could reach network resources outside the management cluster. A user who can supply bundle content to a repository referenced by a GitRepo resource can cause the Fleet controller to disclose cluster metadata and information about hosts reachable from the controller's network position.