CVE-2026-23998

HIGHNVD 7.57.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.2% (11th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3

Also known asEUVD-2026-30368 (ENISA EUVD) · GHSA-2rc4-7jc6-qffh (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Fleet is open source device management software. Prior to version 4.81.0, a vulnerability in Fleet’s Windows MDM management endpoint could allow requests to be processed without proper client certificate validation. In certain circumstances, this could allow an attacker to impersonate an enrolled Windows device and retrieve sensitive configuration data. Fleet’s Windows MDM management endpoint relies on mutual TLS (mTLS) client certificates to authenticate enrolled devices. In affected versions, requests that did not present a client certificate could be incorrectly treated as trusted. As a result, an attacker with prior knowledge of a valid enrolled device identifier could potentially impersonate that device and receive configuration payloads intended for it. These payloads may contain sensitive information such as Wi-Fi or VPN configuration data, certificates, or other secrets delivered through MDM profiles. This issue does not allow enrollment of new devices, administrative access to Fleet, or compromise of the Fleet control plane. Impact is limited to the targeted Windows device. Version 4.81.0 contains a patch. If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
34
EG Risk 34/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
11th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-27). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

May 14, 2026

Last Modified

October 26, 2026

Advisory Details (2)

Auto-updated May 14, 2026
Patch available. Sources: github.
GitHub advisoryMentions a patch (unverified)

Windows MDM management endpoint authentication bypass · Advisory · fleetdm/fleet · GitHub

https://github.com/fleetdm/fleet/security/advisories/GHSA-2rc4-7jc6-qffh
Web page

Release fleet-v4.81.0 · fleetdm/fleet · GitHub

https://github.com/fleetdm/fleet/releases/tag/fleet-v4.81.0

Vendor Advisories for CVE-2026-23998(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFix by version rangeDependents
github.com/fleetdm/fleet/v4—
  • every version up to 4.81.0: fixed in 4.81.0
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 38× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 99 of 230 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 131 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  2. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  3. 2026-10-27 20:54 UTCEG score recompute
  4. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  5. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  6. 2026-10-26 14:36 UTCEG score recompute
  7. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  8. 2026-10-25 14:41 UTCEG score recompute
  9. 2026-10-24 20:14 UTCEG score recompute
  10. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  11. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  12. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  13. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  14. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  15. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  16. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  17. 2026-10-18 03:54 UTCEG score recompute
  18. 2026-10-17 17:02 UTCEG score recompute
  19. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  20. 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  21. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  22. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  23. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  24. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  25. 2026-10-12 16:20 UTCEG score recompute
Show 74 more
  1. 2026-10-11 20:02 UTCEG score recompute
  2. 2026-10-11 17:15 UTCEG score recompute
  3. 2026-10-11 14:47 UTCEG score recompute
  4. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  5. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  6. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  7. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  8. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  9. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  10. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  11. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  12. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  13. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  14. 2026-09-30 04:58 UTCOSV refresh
  15. 2026-09-29 15:21 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  16. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  17. 2026-09-27 13:47 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  18. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  19. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  20. 2026-09-24 14:03 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  21. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  22. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  23. 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  24. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  25. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  26. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  27. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  28. 2026-09-11 07:53 UTCOSV refresh
  29. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  30. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  31. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  32. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  33. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  34. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  35. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  36. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  37. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  38. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  39. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  40. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  41. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  42. 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  43. 2026-08-23 17:38 UTCEG score recompute
  44. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  45. 2026-08-22 01:50 UTCEG score recompute
  46. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  47. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  48. 2026-08-20 19:35 UTCEG score recompute
  49. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  50. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  51. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  52. 2026-08-17 10:22 UTCEG score recompute
  53. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  54. 2026-08-16 03:56 UTCEG score recompute
  55. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  56. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  57. 2026-08-14 02:24 UTCEG score recompute
  58. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  59. 2026-08-12 14:58 UTCEG score recompute
  60. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  61. 2026-08-11 15:24 UTCEG score recompute
  62. 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  63. 2026-08-11 00:52 UTCEG score recompute
  64. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  65. 2026-08-10 00:53 UTCEG score recompute
  66. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  67. 2026-08-09 01:49 UTCEG score recompute
  68. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  69. 2026-08-07 19:46 UTCEG score recompute
  70. 2026-08-06 20:41 UTCEG score recompute
  71. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  72. 2026-08-05 21:35 UTCEG score recompute
  73. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  74. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.2% · 11th percentile

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-23998?
CVE-2026-23998 is a high-severity vulnerability; its CVE record was published on May 14, 2026. Fleet is open source device management software. Prior to version 4.81.0, a vulnerability in Fleet’s Windows MDM management endpoint could allow requests to be processed without proper client certificate validation. In certain circumstances, this could allow an attacker to impersonate an enrolled…
When was the CVE record for CVE-2026-23998 published?
The CVE record for CVE-2026-23998 was published on May 14, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 26, 2026; the record at its source may have been updated since.
Is CVE-2026-23998 actively exploited?
CVE-2026-23998 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (11th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-23998?
CVE-2026-23998 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-23998?
A fix for CVE-2026-23998 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-23998 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-23998

Explore →

Is Your Infrastructure Affected by CVE-2026-23998?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs