Headline
GHSA-52jx-g6m5-h735: Fleet has SAML authentication vulnerability due to improper SAML response validation
Impact
In vulnerable versions of Fleet, an attacker could craft a specially-formed SAML response to:
- Forge authentication assertions, potentially impersonating legitimate users.
- If Just-In-Time (JIT) provisioning is enabled, the attacker could provision a new administrative user account.
- If MDM enrollment is enabled, certain endpoints could be used to create new accounts tied to forged assertions.
This could allow unauthorized access to Fleet, including administrative access, visibility into device data, and modification of configuration.
Patches
This issue is addressed in commit fc96cc4 and is available in Fleet version 4.64.2.
The following backport versions also address this issue:
- 4.63.2
- 4.62.4
- 4.58.1
Workarounds
If an immediate upgrade is not possible, Fleet users should temporarily disable single-sign-on (SSO) and use password authentication.
Credit
Thank you @hakivvi, as well as Jeffrey Hofmann and Colby Morgan from the Robinhood Red Team for finding and reporting this vulnerability using our responsible disclosure process.
For more information
If you have any questions or comments about this advisory:
- Email us at [email protected]
- Join #fleet in osquery Slack
Impact
In vulnerable versions of Fleet, an attacker could craft a specially-formed SAML response to:
- Forge authentication assertions, potentially impersonating legitimate users.
- If Just-In-Time (JIT) provisioning is enabled, the attacker could provision a new administrative user account.
- If MDM enrollment is enabled, certain endpoints could be used to create new accounts tied to forged assertions.
This could allow unauthorized access to Fleet, including administrative access, visibility into device data, and modification of configuration.
Patches
This issue is addressed in commit fc96cc4 and is available in Fleet version 4.64.2.
The following backport versions also address this issue:
- 4.63.2
- 4.62.4
- 4.58.1
Workarounds
If an immediate upgrade is not possible, Fleet users should temporarily disable single-sign-on (SSO) and use password authentication.
Credit
Thank you @hakivvi, as well as Jeffrey Hofmann and Colby Morgan from the Robinhood Red Team for finding and reporting this vulnerability using our responsible disclosure process.
For more information
If you have any questions or comments about this advisory:
- Email us at [email protected]
- Join #fleet in osquery Slack
References
- GHSA-52jx-g6m5-h735
- fleetdm/fleet@718c95e
- https://github.com/fleetdm/fleet/releases/tag/fleet-v4.64.2
- https://nvd.nist.gov/vuln/detail/CVE-2025-27509