Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from GitHub Advisory.
CVSS VectorGitHub Advisory
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
4DescriptionGitHub Advisory
Fleet is open source device management software. Prior to 4.81.0, a denial-of-service vulnerability in Fleet's gRPC Launcher endpoint allows an authenticated host to crash the entire Fleet server process by sending an unexpected log type value. The server terminates immediately, disrupting all connected hosts, MDM enrollments, and API consumers. Version 4.81.0 patches the issue.
AnalysisAI
Denial-of-service vulnerability in Fleet device management software prior to version 4.81.0 allows authenticated hosts to crash the entire Fleet server process by sending a malformed log type value to the gRPC Launcher endpoint, disrupting all connected devices, MDM enrollments, and API consumers. The vulnerability requires prior authentication but affects availability across the entire infrastructure. Vendor-released patch: version 4.81.0.
Technical ContextAI
Fleet's gRPC Launcher endpoint implements log type validation at the application layer. The vulnerability stems from improper input validation (CWE-703: Improper Check or Handling of Exceptional Conditions) where unexpected log type values trigger an uncaught exception or unhandled edge case, causing the server process to terminate abnormally. gRPC is a high-performance RPC framework using Protocol Buffers for serialization; malformed message payloads that violate schema constraints can propagate uncontrolled through the application if validation boundaries are incomplete. The affected product cpe:2.3:a:fleetdm:fleet:*:*:*:*:*:*:*:* encompasses all versions prior to 4.81.0.
RemediationAI
Upgrade Fleet to version 4.81.0 or later, which contains the fix for input validation on the gRPC Launcher endpoint. The patch adds proper exception handling and validation for log type values to prevent server termination on unexpected inputs. Administrators should apply this update urgently, especially in production MDM environments. Refer to the GitHub security advisory at https://github.com/fleetdm/fleet/security/advisories/GHSA-w254-4hp5-7cvv for detailed upgrade instructions and rollout guidance. Until patching is complete, monitor server logs for unexpected exceptions from the Launcher endpoint and implement network segmentation to limit which hosts can reach the gRPC endpoint if available.
Same technique Denial Of Service
View allVendor StatusVendor
SUSE
Severity: HighShare
External POC / Exploit Code
Leaving vuln.today
EUVD-2026-16795
GHSA-w254-4hp5-7cvv