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CVE-2026-24899 high CVSS 7.5

Vulnerability in github.com/fleetdm/fleet/v4 (CVE-2026-24899)

Summary

Vulnerability in github.com/fleetdm/fleet/v4 (CVE-2026-24899). Confidential information can be exposed externally. Exploitable via aud. Mitigation: upgrade to 4.82.0 or later.

Original description

The description as published by the source.

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.

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-24899 has been found in github.com/fleetdm/fleet/v4.
Attackers can target a specific entry point like aud over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.5/10.
What to do: upgrade github.com/fleetdm/fleet/v4 to 4.82.0 or later.
If unsure, ask your IT team or search "github.com/fleetdm/fleet/v4 CVE-2026-24899" on the vendor's site.

CVE-2026-24899 (github.com/fleetdm/fleet/v4) — CWE-290 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: aud / iss
Patched: 4.82.0 — apply immediately
Workaround: If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-290) exists in github.com/fleetdm/fleet/v4. Attackers reach the vulnerable code path via aud without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of github.com/fleetdm/fleet/v4. Attack surface: aud / iss.

🔥 Severity

Severity: High (CVSS 7.5/10). Confidential information can be exposed externally.

🔧 How to fix

Update to 4.82.0.

🛡️ Workaround

Workaround: If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/fleetdm/fleet/v4' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'github.com/fleetdm/fleet/v4' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で github.com/fleetdm/fleet/v4 を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply temporary workaround mitigate 
    If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.

    パッチが適用されるまでの応急処置として、If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM. を実施。回避策の副作用 (機能低下) を確認した上で。

  3. 3
    Apply patch patch 
    Upgrade github.com/fleetdm/fleet/v4 to 4.82.0

    ステージング環境で 4.82.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  4. 4
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

go github.com/fleetdm/fleet/v4
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.82.0"}]}]

References

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