CVE-2026-26061

| EUVD-2026-16744 HIGH
2026-03-27 https://github.com/fleetdm/fleet GHSA-99hj-44vg-hfcp
8.7
CVSS 4.0
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CVSS Vector

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:X/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
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
X

Lifecycle Timeline

4
Patch Released
Mar 31, 2026 - 21:13 nvd
Patch available
Analysis Generated
Mar 27, 2026 - 18:30 vuln.today
EUVD ID Assigned
Mar 27, 2026 - 18:30 euvd
EUVD-2026-16744
CVE Published
Mar 27, 2026 - 18:17 nvd
HIGH 8.7

Description

### Summary Fleet contained multiple unauthenticated HTTP endpoints that read request bodies without enforcing a size limit. An unauthenticated attacker could exploit this behavior by sending large or repeated HTTP payloads, causing excessive memory allocation and resulting in a denial-of-service (DoS) condition. ### Impact An unauthenticated attacker could cause the Fleet server process to exhaust available memory and restart by sending oversized or repeated HTTP requests to affected endpoints. This vulnerability impacts **availability only**. There is: - No exposure of sensitive data - No authentication bypass - No privilege escalation - No integrity impact ### Workarounds If upgrading immediately is not possible, the following mitigations can reduce exposure: - Apply request body size limits at a reverse proxy or load balancer (e.g., NGINX, Envoy). - Restrict network access to endpoints to known IP ranges where feasible. - Monitor memory usage and restart frequency for abnormal patterns. ### For More Information If there are any questions or concerns about this advisory, please contact us at: Email Fleet at [[email protected]](mailto:[email protected]) ### Credits Fleet thanks @fuzzztf for responsibly reporting this issue.

Analysis

Fleet server memory exhaustion via unbounded request bodies allows unauthenticated denial-of-service against multiple HTTP endpoints. The vulnerability affects Fleet v4 (github.com/fleetdm/fleet/v4) and was responsibly disclosed by @fuzzztf. …

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Remediation

Within 24 hours: Implement network-level request size limits and rate limiting on Fleet HTTP endpoints; document current Fleet v4 version in use. Within 7 days: Deploy WAF rules to enforce maximum request body sizes (recommend 1MB limit) on all unauthenticated Fleet endpoints; segment Fleet server network access where feasible. …

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Priority Score

44
Low Medium High Critical
KEV: 0
EPSS: +0.1
CVSS: +44
POC: 0

Vendor Status

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CVE-2026-26061 vulnerability details – vuln.today

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