GHSA-GFPW-JGVR-CW4J

Vulnerability from github – Published: 2026-01-20 20:52 – Updated: 2026-01-22 15:38
VLAI?
Summary
Fleet Windows MDM endpoint has a Cross-site Scripting vulnerability
Details

Summary

A cross-site scripting (XSS) vulnerability in Fleet’s Windows MDM authentication flow could allow an attacker to compromise a Fleet user account. In certain cases, this could lead to administrative access and the ability to perform privileged actions on managed devices.

Impact

If Windows MDM is enabled, an attacker could exploit a cross-site scripting (XSS) vulnerability by convincing an authenticated Fleet user to visit a malicious link. Successful exploitation could allow retrieval of the user’s Fleet authentication token from their browser.

A compromised authentication token may grant administrative access to the Fleet API, allowing an attacker to perform privileged actions such as deploying scripts to managed hosts.

This issue does not allow unauthenticated access and does not affect instances where Windows MDM is disabled.

Patches

  • 4.78.2
  • 4.77.1
  • 4.76.2
  • 4.75.2
  • 4.53.3

Workarounds

If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.

For more information

If you have any questions or comments about this advisory:

Email us at security@fleetdm.com Join #fleet in osquery Slack

Credits

We thank @secfox-ai for responsibly reporting this issue.

Severity ?
5.5 (Medium)
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/fleetdm/fleet"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.78.0"
            },
            {
              "fixed": "4.78.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/fleetdm/fleet"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.77.0"
            },
            {
              "fixed": "4.77.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/fleetdm/fleet"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.76.0"
            },
            {
              "fixed": "4.76.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/fleetdm/fleet"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.75.0"
            },
            {
              "fixed": "4.75.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/fleetdm/fleet/v4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.43.5-0.20260111020427-0e6c790803d1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-22808"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-01-20T20:52:17Z",
    "nvd_published_at": "2026-01-21T22:15:49Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nA cross-site scripting (XSS) vulnerability in Fleet\u2019s Windows MDM authentication flow could allow an attacker to compromise a Fleet user account. In certain cases, this could lead to administrative access and the ability to perform privileged actions on managed devices.\n\n### Impact\n\nIf Windows MDM is enabled, an attacker could exploit a cross-site scripting (XSS) vulnerability by convincing an authenticated Fleet user to visit a malicious link. Successful exploitation could allow retrieval of the user\u2019s Fleet authentication token from their browser.\n\nA compromised authentication token may grant administrative access to the Fleet API, allowing an attacker to perform privileged actions such as deploying scripts to managed hosts.\n\nThis issue does not allow unauthenticated access and does not affect instances where Windows MDM is disabled.\n\n### Patches\n\n- 4.78.2\n- 4.77.1\n- 4.76.2\n- 4.75.2\n- 4.53.3\n\n### Workarounds\n\nIf an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n\nEmail us at [security@fleetdm.com](mailto:security@fleetdm.com)\nJoin #fleet in [osquery Slack](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw)\n\n### Credits\n\nWe thank @secfox-ai for responsibly reporting this issue.",
  "id": "GHSA-gfpw-jgvr-cw4j",
  "modified": "2026-01-22T15:38:41Z",
  "published": "2026-01-20T20:52:17Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/fleetdm/fleet/security/advisories/GHSA-gfpw-jgvr-cw4j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-22808"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fleetdm/fleet/commit/0e6c790803d1b4407c5b4b41a67a37864a3d3573"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/fleetdm/fleet"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Fleet Windows MDM endpoint has a Cross-site Scripting vulnerability"
}


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Nomenclature

  • 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.



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