CVE-2026-45498

CRITICALNVD 7.59.0
EchelonGraph scoreHIGH confidence

“▲” beside the score: it is higher than NVD's CVSS score.

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-05-20), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 7.5 retained for reference. The 9.0 is the floor for confirmed exploitation, not an impact rating: this CVE's impact severity (EG Severity) is CVSS 7.5 HIGH under NVD CVSS v3. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: CISA Known Exploited Vulnerabilities catalog, EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 4 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV) — the reason this is sooner than the SSVC decision on this page at every mission impact level
CISA-KEV: ExploitedEPSS PROB: 1.3%CVSS: 7.5Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Microsoft Defender Denial of Service Vulnerability

CVSS v3
7.5
EG Score
9.0CRITICALhigh confidence
EG Risk
74
EG Risk 74/100

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.
Exploitation100% × 40%
Fixed at 100% for a CISA KEV listing: EchelonGraph's rule.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation active (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
1.3%
EPSS %ILE
69th
KEV
⚠ Exploited

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

The EG score (9.0): severity, escalated by confirmed exploitation. This CVE's 9.0 is the CISA KEV floor for confirmed exploitation, not an impact rating: its impact severity (EG Severity) is CVSS 7.5 HIGH.

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
1.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-22). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
CISA KEV and EG-KEV Tier 1 (exploited in the wild)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 14 days 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 low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation active (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)14 days if the affected system is publicly exposed; 14 days if it is not.

In CISA KEV yes (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

CISA required action“Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.”

Quoted verbatim from CISA's Known Exploited Vulnerabilities catalog. CISA directs it at US federal civilian executive branch agencies under Binding Operational Directive (BOD) 26-04, which replaced BOD 22-01 on 10 June 2026; it is not EchelonGraph's advice. CISA's notes: https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-45498 · https://nvd.nist.gov/vuln/detail/CVE-2026-45498

Published

May 20, 2026

Last Modified

August 10, 2026

Advisory Details (1)

Auto-updated Oct 20, 2026
⚠️ Actively exploited (CISA KEV, CISA Vulnrichment). Patch available. Sources: microsoft.
Microsoft

Security Update Guide - Microsoft Security Response Center

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45498

Vendor Advisories for CVE-2026-45498(2)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 24× in last 7d / 292× 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 100 of 1,776 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. None are among the latest 100 rows. The 1,676 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-23 16:31 UTCEPSS rescoreEPSS 1.3% · 69th percentile
  2. 2026-10-23 13:41 UTCEG score recompute
  3. 2026-10-23 13:40 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  4. 2026-10-22 16:34 UTCEPSS rescoreEPSS 1.3% · 69th percentile
  5. 2026-10-22 13:08 UTCEG score recompute
  6. 2026-10-22 13:08 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  7. 2026-10-21 16:33 UTCEPSS rescoreEPSS 1.3% · 69th percentile
  8. 2026-10-21 12:35 UTCEG score recompute
  9. 2026-10-21 12:35 UTCVendor advisory
  10. 2026-10-21 12:35 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  11. 2026-10-20 16:33 UTCEPSS rescoreEPSS 1.3% · 69th percentile
  12. 2026-10-20 12:01 UTCEG score recompute
  13. 2026-10-20 12:01 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  14. 2026-10-19 16:32 UTCEPSS rescoreEPSS 1.3% · 69th percentile
  15. 2026-10-19 11:29 UTCEG score recompute
  16. 2026-10-19 11:29 UTCVendor advisory
  17. 2026-10-19 11:29 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  18. 2026-10-18 16:32 UTCEPSS rescoreEPSS 1.3% · 69th percentile
  19. 2026-10-18 10:56 UTCVendor advisory
  20. 2026-10-18 10:56 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  21. 2026-10-18 03:38 UTCEG score recompute
  22. 2026-10-17 16:34 UTCEPSS rescoreEPSS 1.3% · 69th percentile
  23. 2026-10-17 10:24 UTCEG score recompute
  24. 2026-10-17 10:24 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  25. 2026-10-16 16:42 UTCEPSS rescoreEPSS 1.3% · 69th percentile
Show 75 more
  1. 2026-10-16 09:52 UTCEG score recompute
  2. 2026-10-16 09:52 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  3. 2026-10-15 16:32 UTCEPSS rescoreEPSS 1.3% · 69th percentile
  4. 2026-10-15 09:20 UTCEG score recompute
  5. 2026-10-15 09:20 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  6. 2026-10-14 16:33 UTCEPSS rescoreEPSS 1.3% · 69th percentile
  7. 2026-10-14 08:46 UTCEG score recompute
  8. 2026-10-14 08:46 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  9. 2026-10-13 16:34 UTCEPSS rescoreEPSS 1.3% · 69th percentile
  10. 2026-10-13 08:16 UTCEG score recompute
  11. 2026-10-13 08:16 UTCVendor advisory
  12. 2026-10-13 08:15 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  13. 2026-10-12 16:34 UTCEPSS rescoreEPSS 1.3% · 68th percentile
  14. 2026-10-12 16:04 UTCEG score recompute
  15. 2026-10-12 07:43 UTCVendor advisory
  16. 2026-10-12 07:43 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  17. 2026-10-12 03:39 UTCVendor advisory
  18. 2026-10-12 03:39 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  19. 2026-10-11 23:35 UTCVendor advisory
  20. 2026-10-11 23:34 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  21. 2026-10-11 19:30 UTCEG score recompute
  22. 2026-10-11 19:30 UTCVendor advisory
  23. 2026-10-11 19:30 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  24. 2026-10-11 17:01 UTCEG score recompute
  25. 2026-10-11 15:27 UTCVendor advisory
  26. 2026-10-11 15:27 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  27. 2026-10-11 14:26 UTCEG score recompute
  28. 2026-10-11 13:48 UTCEPSS rescoreEPSS 1.3% · 68th percentile
  29. 2026-10-11 11:25 UTCEG score recompute
  30. 2026-10-11 11:25 UTCVendor advisory
  31. 2026-10-11 11:25 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  32. 2026-10-11 07:22 UTCVendor advisory
  33. 2026-10-11 07:22 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  34. 2026-10-11 03:18 UTCVendor advisory
  35. 2026-10-11 03:18 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  36. 2026-10-10 23:14 UTCEG score recompute
  37. 2026-10-10 23:14 UTCVendor advisory
  38. 2026-10-10 23:14 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  39. 2026-10-10 20:00 UTCEPSS rescoreEPSS 1.3% · 68th percentile
  40. 2026-10-10 19:10 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  41. 2026-10-10 15:06 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  42. 2026-10-10 11:03 UTCVendor advisory
  43. 2026-10-10 11:03 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  44. 2026-10-10 07:00 UTCVendor advisory
  45. 2026-10-10 07:00 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  46. 2026-10-10 02:57 UTCVendor advisory
  47. 2026-10-10 02:57 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  48. 2026-10-09 22:54 UTCEG score recompute
  49. 2026-10-09 22:54 UTCVendor advisory
  50. 2026-10-09 22:53 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  51. 2026-10-09 20:07 UTCEPSS rescoreEPSS 1.3% · 68th percentile
  52. 2026-10-09 18:51 UTCVendor advisory
  53. 2026-10-09 18:50 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  54. 2026-10-09 14:47 UTCVendor advisory
  55. 2026-10-09 14:47 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  56. 2026-10-09 10:40 UTCVendor advisory
  57. 2026-10-09 10:40 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  58. 2026-10-09 06:37 UTCVendor advisory
  59. 2026-10-09 06:37 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  60. 2026-10-09 02:33 UTCVendor advisory
  61. 2026-10-09 02:33 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  62. 2026-10-08 22:31 UTCVendor advisory
  63. 2026-10-08 22:30 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  64. 2026-10-08 18:27 UTCEG score recompute
  65. 2026-10-08 18:27 UTCVendor advisory
  66. 2026-10-08 18:27 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  67. 2026-10-08 17:12 UTCEPSS rescoreEPSS 1.3% · 68th percentile
  68. 2026-10-08 14:24 UTCVendor advisory
  69. 2026-10-08 14:24 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  70. 2026-10-08 10:19 UTCVendor advisory
  71. 2026-10-08 10:19 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  72. 2026-10-08 06:16 UTCVendor advisory
  73. 2026-10-08 06:16 UTCGHSA enrichmentGHSA-8gp3-pghr-6wxp · GitHub CVSS 4.0
  74. 2026-10-08 02:13 UTCEG score recompute
  75. 2026-10-08 02:13 UTCVendor advisory

Frequently asked(6)

What is CVE-2026-45498?
CVE-2026-45498 is a critical-severity vulnerability; its CVE record was published on May 20, 2026. Microsoft Defender Denial of Service Vulnerability
When was CVE-2026-45498 made public?
CVE-2026-45498 was made public on May 19, 2026: that is the date its CVE record's CNA, Microsoft Corporation, gives for when the vulnerability was made public. The CVE record itself was published on May 20, 2026. EchelonGraph's copy of the record carries a last-modified date of August 10, 2026; the record at its source may have been updated since.
Is CVE-2026-45498 actively exploited?
Yes. CISA added CVE-2026-45498 to the Known Exploited Vulnerabilities catalog on May 20, 2026, affecting Microsoft Defender. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate attention. A fix is available. Apply it.
What is the CVSS score of CVE-2026-45498?
CVE-2026-45498 has a CVSS v3 base score of 7.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0 (CRITICAL).
Which products are affected by CVE-2026-45498?
CVE-2026-45498 affects Microsoft Defender.
How do I remediate CVE-2026-45498?
A fix for CVE-2026-45498 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-45498 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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