GHSA-ffg9-j72f-j6xm CVE-2026-24899 GO-2026-5358
Fleet Windows MDM Azure AD JWT Authentication Bypass
- Severity
- 0.0 / 10
- High · CVSS 4.0
- Exploit chance (EPSS)
- 0.38%
- Chance of exploitation in the next 30 days. Higher than 32.10% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-290 Authentication Bypass by Spoofing
- Fix
4.82.0- Upgrade github.com/fleetdm/fleet/v4 to this version or later
Description
Summary
A vulnerability in Fleet's Windows MDM enrollment flow allows authentication tokens from any Azure AD tenant to be accepted. Because Fleet validates JWT signatures using Microsoft's multi-tenant JWKS endpoint but does not enforce the aud (audience) or iss (issuer) claims, any Microsoft-signed Azure AD access token containing the expected scopes can be used to authenticate to Fleet's MDM endpoints.
Impact
If Windows MDM is enabled, an attacker with access to any Azure AD tenant can obtain a valid Microsoft-signed token and use it to enroll unauthorized devices and interact with Fleet's MDM management APIs. During device management, Fleet may expose sensitive enrollment secrets embedded in MDM command payloads, enabling further unauthorized access.
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 @zaddy6 for responsibly reporting this issue.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/fleetdm/fleet/v4 | < 4.82.0 |
4.82.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/fleetdm/fleet/v4 Go → 4.82.0
- go
go get github.com/fleetdm/fleet/v4@v4.82.0 && go mod tidy
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- High
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- High
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Weakness
CWE-290: Authentication Bypass by Spoofing
This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-rxhg-vcww-2mpw Fleet: ORDER BY column injection on activity list endpoints | Low | Also affects github.com/fleetdm/fleet/v4 |
| GHSA-q9c5-pp7m-fm2g Fleet: Unauthenticated download of in-house iOS app binaries via predictable URLs | Medium | Also affects github.com/fleetdm/fleet/v4 |
| GO-2026-6264 Fleet: SQL injection in Okta conditional access endpoint allows host-controlled compromise of the Fleet database | High | Also affects github.com/fleetdm/fleet/v4 |
| GHSA-88p2-jj8w-j8qg Fleet: Observer-class users can view team enroll secrets and credential-bearing configuration via target search endpoint | Medium | Also affects github.com/fleetdm/fleet/v4 |
| GHSA-gm7f-v959-fr2g Fleet DM Vulnerable to Cross-Team Policy Data Exposure via Global Policy Read Endpoint | Medium | Also affects github.com/fleetdm/fleet/v4 |
| GHSA-x4qr-qw6h-wvxq Fleet: Observer-level enrollment secret extraction via ORDER BY oracle on Apple MDM commands endpoint | Medium | Also affects github.com/fleetdm/fleet/v4 |
| GHSA-vxm7-9x8v-8gm4 Fleet has observer-level enrollment secret extraction via ORDER BY oracle on labels host-listing endpoint | Medium | Also affects github.com/fleetdm/fleet/v4 |
| GHSA-mxmp-wr3w-rvqx Fleet: IP spoofing allows bypassing API rate limiting | High | Also affects github.com/fleetdm/fleet/v4 |
MergeHarbor checks every repository's dependencies against this database, ranks what matters by exploitability and reachability, routes it to the owning team and opens the fix pull request.
Check your repos with MergeHarbor