Get a Demo

Let's Patch It!

Book a short call with one our specialists, we'll walk you through how Endor Patches work, and ask you a few questions about your environment (like your primary programming languages and repository management). We'll also send you an email right after you fill out the form, feel free to reply with any questions you have in advance!

CVE

CVE-2026-34388

Fleet vulnerable to Denial of Service via unhandled gRPC log type in launcher endpoint
Back to all
CVE

CVE-2026-34388

Fleet vulnerable to Denial of Service via unhandled gRPC log type in launcher endpoint

Summary

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.

Impact

An attacker with access to a valid Launcher node key can send a specially crafted gRPC request to the Fleet server that triggers an unrecoverable server crash. The gRPC server lacks appropriate error recovery handling, meaning the entire Fleet process terminates rather than gracefully rejecting the malformed input.

Because the crash is instant and repeatable, an attacker could script repeated requests to prevent the server from recovering, resulting in a persistent denial of service until a patched version is deployed.

Workarounds

There is no workaround for this issue other than upgrading to a patched version.

For more information

If there are any questions or comments about this advisory:

Send an email to  security@fleetdm.com

Join #fleet in osquery Slack

Credits

Fleet thanks @fuzzztf for responsibly reporting this issue.

Package Versions Affected

Package Version
patch Availability
No items found.

Automatically patch vulnerabilities without upgrading

Fix Without Upgrading
Detect compatible fix
Apply safe remediation
Fix with a single pull request

CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
6.6
-
4.0
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
C
H
U
0
-
C
H
U
-

Related Resources

No items found.

References

https://github.com/fleetdm/fleet/security/advisories/GHSA-w254-4hp5-7cvv, https://nvd.nist.gov/vuln/detail/CVE-2026-34388, https://github.com/fleetdm/fleet

Severity

7.5

CVSS Score
0
10

Basic Information

Ecosystem
Base CVSS
7.5
EPSS Probability
0.00063%
EPSS Percentile
0.19824%
Introduced Version
0
Fix Available
4.81.0

Fix Critical Vulnerabilities Instantly

Secure your app without upgrading.
Fix Without Upgrading