GHSA-99HJ-44VG-HFCP

Vulnerability from github – Published: 2026-03-27 18:17 – Updated: 2026-03-27 21:47
VLAI?
Summary
Fleet's unbounded request body read allows remote Denial of Service
Details

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 security@fleetdm.com

Credits

Fleet thanks @fuzzztf for responsibly reporting this issue.

Severity ?
8.7 (High)
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
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/fleetdm/fleet/v4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.43.5-0.20260113202849-bbc1aef2987d"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-26061"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-27T18:17:42Z",
    "nvd_published_at": "2026-03-27T19:16:42Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n\nFleet 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.\n\n### Impact\n\nAn unauthenticated attacker could cause the Fleet server process to exhaust available memory and restart by sending oversized or repeated HTTP requests to affected endpoints.\n\nThis vulnerability impacts **availability only**. There is:\n\n- No exposure of sensitive data\n- No authentication bypass\n- No privilege escalation\n- No integrity impact\n\n### Workarounds\n\nIf upgrading immediately is not possible, the following mitigations can reduce exposure:\n\n- Apply request body size limits at a reverse proxy or load balancer (e.g., NGINX, Envoy).\n- Restrict network access to endpoints to known IP ranges where feasible.\n- Monitor memory usage and restart frequency for abnormal patterns.\n\n### For More Information\n\nIf there are any questions or concerns about this advisory, please contact us at:\n\nEmail Fleet at [security@fleetdm.com](mailto:security@fleetdm.com)\n\n### Credits\n\nFleet thanks @fuzzztf for responsibly reporting this issue.",
  "id": "GHSA-99hj-44vg-hfcp",
  "modified": "2026-03-27T21:47:50Z",
  "published": "2026-03-27T18:17:42Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/fleetdm/fleet/security/advisories/GHSA-99hj-44vg-hfcp"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-26061"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/fleetdm/fleet"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Fleet\u0027s unbounded request body read allows remote Denial of Service"
}


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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.