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  5. CVE-2025-27509

CVE-2025-27509: Fleet has SAML authentication vulnerability due to improper SAML response validation

March 6, 2025 (updated January 21, 2026)

A vulnerability in Fleet’s SAML authentication handling could allow an attacker to forge authentication assertions and gain unauthorized access to Fleet. In certain configurations, this could result in the creation of new user accounts, including administrative accounts. This issue affects Fleet deployments using single sign-on (SSO).

References

  • github.com/advisories/GHSA-52jx-g6m5-h735
  • github.com/fleetdm/fleet
  • github.com/fleetdm/fleet/commit/718c95e47ad010ad6b8ceb3f3460e921fbfc53bb
  • github.com/fleetdm/fleet/releases/tag/fleet-v4.64.2
  • github.com/fleetdm/fleet/security/advisories/GHSA-52jx-g6m5-h735
  • nvd.nist.gov/vuln/detail/CVE-2025-27509
  • pkg.go.dev/vuln/GO-2025-3505

Code Behaviors & Features

Detect and mitigate CVE-2025-27509 with GitLab Dependency Scanning

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Affected versions

All versions before 4.53.2, all versions starting from 4.54.0 before 4.58.1, all versions starting from 4.62.0 before 4.62.4, all versions starting from 4.63.0 before 4.63.2, all versions starting from 4.64.0 before 4.64.2

Fixed versions

  • 4.64.2
  • 4.63.2
  • 4.62.4
  • 4.58.1
  • 4.53.2

Solution

Upgrade to versions 4.53.2, 4.58.1, 4.62.4, 4.63.2, 4.64.2 or above.

Impact 9.1 CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Learn more about CVSS

Weakness

  • CWE-285: Improper Authorization
  • CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Source file

go/github.com/fleetdm/fleet/v4/CVE-2025-27509.yml

Spotted a mistake? Edit the file on GitLab.

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