CVE-2026-26062
MEDIUMFleet 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,…
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
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.
Affected Products
fleetfleetdmDetection & mitigation playbook
Vendor / applianceDetect
Inventory every fleetdm fleet deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Fix
Apply the fleetdm fleet security patch or hotfix for CVE-2026-26062 on the affected version, following the vendor advisory for your exact build.
Workarounds
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2026-26062 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-2026-26062. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-26062 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2026-26062 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.