GHSA-52jx-g6m5-h735
Fleet has SAML authentication vulnerability due to improper SAML response validation
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
github.com/fleetdm/fleet/v4🐹github.com/fleetdm/fleet/v4🐹github.com/fleetdm/fleet/v4🐹github.com/fleetdm/fleet/v4🐹github.com/fleetdm/fleet/v4Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
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).
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
- 4.53.2
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
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/fleetdm/fleet/v4 | ≥ 4.64.0&&< 4.64.2 | 4.64.2 |
| 🐹Go | github.com/fleetdm/fleet/v4 | ≥ 4.63.0&&< 4.63.2 | 4.63.2 |
| 🐹Go | github.com/fleetdm/fleet/v4 | ≥ 4.62.0&&< 4.62.4 | 4.62.4 |
| 🐹Go | github.com/fleetdm/fleet/v4 | ≥ 4.54.0&&< 4.58.1 | 4.58.1 |
| 🐹Go | github.com/fleetdm/fleet/v4 | all versions | 4.53.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/fleetdm/fleet/v4. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/fleetdm/fleet/v4 to 4.64.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-52jx-g6m5-h735 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-52jx-g6m5-h735 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-52jx-g6m5-h735. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-52jx-g6m5-h735 in your dependencies?
O3 detects GHSA-52jx-g6m5-h735 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.