CVE-2026-34388
highpriority · track · 30EPSS 0.003 · 20 %ileDEEUUSEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.6–7.5
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (5)
Products and version ranges known to be affected.
advisories (3)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-0902Fleet: Mehrere SchwachstellenDeutsch2026-03-29csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Fleet ausnutzen, um einen SQL-Injection Angriff durchzuführen, um einen Denial of Service Angriff durchzuführen, um Sicherheitsvorkehrungen zu umgehen, um Informationen offenzulegen, und um beliebigen Programmcode mit Administratorrechten auszuführen.
- GHSA-w254-4hp5-7cvvFleet vulnerable to Denial of Service via unhandled gRPC log type in launcher endpoint2026-03-30ghsa · osvUS
### 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](mailto:security@fleetdm.com) Join #fleet in [osquery Slack](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw) ### Credits Fleet thanks @fuzzztf for responsibly reporting this issue.
- GO-2026-4915Fleet vulnerable to Denial of Service via unhandled gRPC log type in launcher endpoint in github.com/fleetdm/fleet2026-04-02vendor · osvUS
Fleet vulnerable to Denial of Service via unhandled gRPC log type in launcher endpoint in github.com/fleetdm/fleet
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (5)
External citations — patches, advisories, analysis.
- https://access.redhat.com/security/cve/cve-2026-34388cnnvd
- https://github.com/fleetdm/fleet/releasesPatchcnnvd
- https://github.com/fleetdm/fleet/security/advisories/GHSA-w254-4hp5-7cvvcnnvd
- https://github.com/fleetdm/fleet/security/advisories/GHSA-w254-4hp5-7cvvenisa_euvd
- https://github.com/fleetdm/fleet/security/advisories/GHSA-w254-4hp5-7cvvVendor Advisorynvd
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