Is CVE-2026-23518 in the CISA KEV catalog?

No. CVE-2026-23518 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-23518?

CVE-2026-23518 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2026-23518?

CVE-2026-23518 has an EPSS score of 0.23% (13th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-23518?

Upgrade fleet to 4.78.3 or later.

CVE & CISA-KEV Catalog

CVE-2026-23518

CRITICAL

9.8

CVSS v3

NVD

Description

Fleet is open source device management software. In versions prior to 4.78.3, 4.77.1, 4.76.2, 4.75.2, and 4.53.3, a vulnerability in Fleet's Windows MDM enrollment flow could allow an attacker to submit forged authentication tokens that are not properly validated. Because JWT signatures were not verified, Fleet could accept attacker-controlled identity claims, enabling enrollment of unauthorized devices under arbitrary Azure AD user identities. Versions 4.78.3, 4.77.1, 4.76.2, 4.75.2, and 4.53.3 fix the issue. If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.

CWE-347

How to fix

Remediation Available

fleetNVD

Affected:>= 4.78.0, < 4.78.3Fixed in:4.78.3CVE-2026-23518derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.23%probability of exploitation in 30 days

13thpercentile

Low risk: more likely to be exploited than 13% of all known CVEs.

References

Patch1

github.com

Vendor Advisory1

github.com

Related Vulnerabilities

Other CWE-347 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2018-16042	Medium	6.5	82%	-	-
CVE-2025-59718	Critical	9.8	66%	KEV	Fix
CVE-2025-25292	Critical	9.8	64%	-	Fix
CVE-2021-22160	Critical	9.8	53%	-	Fix
CVE-2013-3900	Medium	5.5	45%	KEV	-
CVE-2018-0114	High	7.5	43%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-02-27.