CVE-2026-26062: fleetdm fleet Improper Input Validation

Vulnerability summary

CVE-2026-26062 is a high (CVSS 8.7) Improper Input Validation vulnerability in fleetdm fleet. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 44.4% of scored vulnerabilities.

Timeline

1. 14-05-2026
   PublishedVulnerability first disclosed.
2. 14-05-2026
   Last modifiedVulnerability information updated.

Description

Fleet is open source device management software. Prior to version 4.81.0, Fleet contained a denial-of-service (DoS) issue in the gRPC Launcher `PublishLogs` endpoint. In affected versions, certain unexpected input values were not handled gracefully, which could cause the Fleet server process to terminate while processing an authenticated request from an enrolled Launcher host. An authenticated attacker with access to any enrolled Launcher node key could cause an immediate and complete denial of service by sending a single gRPC request to the `PublishLogs` endpoint. This vulnerability impacts availability only. There is no exposure of sensitive data, no authentication bypass, no privilege escalation, and no integrity impact. Version 4.81.0 contains a patch. If upgrading immediately is not possible, the following mitigations can reduce exposure. Restrict network access to the Fleet gRPC endpoint where feasible (for example, limiting inbound access to known host IP ranges); deploy Fleet behind infrastructure that terminates or filters gRPC traffic if Launcher log ingestion is not required; and/or monitor for repeated Fleet process crashes or unexpected restarts indicating potential exploitation.

• CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.