9.8

CVE-2026-23518: fleetdm fleet

CVSS: 9.8v3.1CriticalAnalyzed
AliasesGHSA-63m5-974w-448vGO-2026-4335
Published 21-01-2026Last modified 22-01-2026
Open JSON

Vulnerability summary

CVE-2026-23518 is a critical (CVSS 9.8) vulnerability in fleetdm fleet. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.9% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.8/10
010
Critical · v3.1 (NVD)
EPSS score
0.25%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 2
OPENSUSE-SU-2026:21483-1SUSE-SU-2026:0403-1

Timeline

  1. 21-01-2026
    PublishedVulnerability first disclosed.
  2. 22-01-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

0.25%

Chance of exploitation in the next 30 days

Percentile

16%

Versus all other CVEs

30-day change

0.00 pp

From 0.26% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.25%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Fleetdm1 product
  • fleet≥ 4.77.0, < 4.77.1 | < 4.53.3 | ≥ 4.75.0, < 4.75.2 | ≥ 4.76.0, < 4.76.2 | ≥ 4.78.0, < 4.78.3 | 4.77.0
Github.com/fleetdm1 product
  • fleet≥ 4.78.0, < 4.78.3 | ≥ 4.77.0, < 4.77.1 | ≥ 4.76.0, < 4.76.2 | ≥ 4.75.0, < 4.75.2 | < 4.43.5-0.20260112202845-e225ef57912c
Github.com/fleetdm/fleet1 product
  • v4≥ 4.78.0, < 4.78.3

3 vendors · 3 products

References

5 links