CVE-2026-26062 Fleet server may terminate unexpectedly when handling certain gRPC requests
An authenticated attacker can crash the Fleet server by sending a malformed gRPC request to the PublishLogs endpoint, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-26062?
CVE-2026-26062 is a high-severity denial of service vulnerability in fleetdm fleet, published on 14 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-20
Which versions are affected by CVE-2026-26062?
3 open source packages ship an affected version, including github.com/fleetdm/fleet/v4. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/fleetdm/fleet/v4 Go | All versions | 4.81.0 |
github.com/fleetdm/fleet/v4 Go | All versions | 4.81.0 |
github.com/fleetdm/fleet/v4 Go | All versions | 4.81.0 |
Products include Fleetdm Fleet.
How do I fix CVE-2026-26062?
Upgrade github.com/fleetdm/fleet/v4 to 4.81.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-26062 being exploited?
There is no known exploitation of CVE-2026-26062 in the wild and no public exploit code.
Other vulnerabilities in fleetdm fleet
- CVE-2020-26276 SAML authentication vulnerability in Fleet
- CVE-2026-103264 Fleet before 4.87.0 Authentication Bypass via Device Identifiers
- CVE-2026-23518 Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment
- CVE-2026-26061 Fleet's unbounded request body read allows remote Denial of Service
- CVE-2026-23998 Fleet has a Windows MDM management endpoint authentication bypass
Sources
Also known as GHSA-x67p-9m2r-fxqv, GO-2026-5744.