Auth bypass in Fleet MDM enrollment could disrupt device management; widely used open-source product.
CVE-2026-23518
Auth bypass in Fleet MDM enrollment: forged tokens; JWTs not validated.
Is CVE-2026-23518 being exploited?
Not confirmed. CVE-2026-23518 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.24% probability of exploitation in the next 30 days.
How severe is CVE-2026-23518?
CVE-2026-23518 is rated Critical with a CVSS score of 9.3. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-23518?
Yes. A fix has been recorded for CVE-2026-23518. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-23518 affect?
CVE-2026-23518 affects Fleet MDM Windows enrollment (versions < fixed). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-23518?
Upgrade to the latest patched Fleet version; if not possible, disable Windows MDM temporarily.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker can enroll devices under arbitrary Azure AD identities via forged tokens; authentication bypass.
Immediate action required
- affected>= 4.78.0 and < 4.78.3
- affected>= 4.77.0 and < 4.77.1
- affected>= 4.76.0 and < 4.76.2
- affected>= 4.75.0 and < 4.75.2
- affected< 4.53.3
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.