Improper Verification of Cryptographic Signature Affecting github.com/fleetdm/fleet/server/mdm/microsoft package, versions <4.75.2>=4.76.0 <4.76.2>=4.77.0 <4.77.1>=4.78.0 <4.78.3
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-GOLANG-GITHUBCOMFLEETDMFLEETSERVERMDMMICROSOFT-15046270
- published21 Jan 2026
- disclosed20 Jan 2026
- creditPrateek Tiwari
Introduced: 20 Jan 2026
CVE-2026-23518 Â (opens in a new tab)How to fix?
Upgrade github.com/fleetdm/fleet/server/mdm/microsoft to version 4.75.2, 4.76.2, 4.77.1, 4.78.3 or higher.
Overview
Affected versions of this package are vulnerable to Improper Verification of Cryptographic Signature via the JWT verification process. An attacker can gain unauthorized enrollment of rogue devices by submitting a forged JWT with arbitrary identity claims, as the system fails to verify the signature and accepts tokens not issued by the legitimate authority. This is only exploitable if Windows MDM is enabled.
Workaround
This vulnerability can be mitigated by temporarily disabling Windows MDM.