CVE-2026-21533

CRITICALNVD 7.89.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-02-10), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 7.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 5 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)
CISA-KEV: ExploitedEPSS PROB: 4%CVSS: 7.8Exploit: cisa kev · ssvc active · public exploitExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Improper privilege management in Windows Remote Desktop allows an authorized attacker to elevate privileges locally.

CVSS v3
7.8
EG Score
9.0(high)
EG Risk
81(Attend)
EG Risk 81/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation100% × 40%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
4%
EPSS %ILE
90%
KEV
⚠ Exploited

Published

February 10, 2026

Last Modified

August 19, 2026

Advisory Details (4)

Auto-updated Jun 3, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: microsoft, cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21533
generic🔴 Active Exploitation

CVE-2026-21533 Mitigation Script - Privilege Escalation Vulnerability in Windows Remote Desktop - vsociety

https://www.vicarius.io/vsociety/posts/cve-2026-21533-mitigation-script-privilege-escalation-vulnerability-in-windows-remote-desktop
generic🔴 Active Exploitation

CVE-2026-21533 Detection Script - Privilege Escalation Vulnerability in Windows Remote Desktop - vsociety

https://www.vicarius.io/vsociety/posts/cve-2026-21533-detection-script-privilege-escalation-vulnerability-in-windows-remote-desktop
microsoft Patch Available

Security Update Guide - Microsoft Security Response Center

Security Update Guide - Microsoft Security Response Center. Patch available via Microsoft Security Update

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21533

Weakness Classification(1)

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

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 102× in last 7d / 416× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 1,521 total refreshes for this CVE.

  1. 2026-09-22 15:04 UTCEG score recompute
  2. 2026-09-22 15:04 UTCVendor advisory
  3. 2026-09-22 15:04 UTCGHSA enrichment
  4. 2026-09-22 11:05 UTCVendor advisory
  5. 2026-09-22 11:05 UTCGHSA enrichment
  6. 2026-09-22 07:07 UTCVendor advisory
  7. 2026-09-22 07:06 UTCGHSA enrichment
  8. 2026-09-22 03:08 UTCVendor advisory
  9. 2026-09-22 03:08 UTCGHSA enrichment
  10. 2026-09-21 23:08 UTCEG score recompute
  11. 2026-09-21 23:08 UTCVendor advisory
  12. 2026-09-21 23:08 UTCGHSA enrichment
  13. 2026-09-21 19:09 UTCVendor advisory
  14. 2026-09-21 19:09 UTCGHSA enrichment
  15. 2026-09-21 19:09 UTCCISA KEV update
  16. 2026-09-21 15:10 UTCVendor advisory
  17. 2026-09-21 15:10 UTCGHSA enrichment
  18. 2026-09-21 11:11 UTCVendor advisory
  19. 2026-09-21 11:11 UTCGHSA enrichment
  20. 2026-09-21 07:12 UTCVendor advisory
  21. 2026-09-21 07:12 UTCGHSA enrichment
  22. 2026-09-21 03:12 UTCVendor advisory
  23. 2026-09-21 03:12 UTCGHSA enrichment
  24. 2026-09-20 23:12 UTCEG score recompute
  25. 2026-09-20 23:12 UTCVendor advisory
Show 75 more
  1. 2026-09-20 23:12 UTCGHSA enrichment
  2. 2026-09-20 20:15 UTCEPSS rescore
  3. 2026-09-20 19:12 UTCVendor advisory
  4. 2026-09-20 19:12 UTCGHSA enrichment
  5. 2026-09-20 15:13 UTCVendor advisory
  6. 2026-09-20 15:12 UTCGHSA enrichment
  7. 2026-09-20 11:13 UTCVendor advisory
  8. 2026-09-20 11:13 UTCGHSA enrichment
  9. 2026-09-20 07:13 UTCVendor advisory
  10. 2026-09-20 07:13 UTCGHSA enrichment
  11. 2026-09-20 03:14 UTCVendor advisory
  12. 2026-09-20 03:14 UTCGHSA enrichment
  13. 2026-09-19 23:15 UTCVendor advisory
  14. 2026-09-19 23:15 UTCGHSA enrichment
  15. 2026-09-19 19:16 UTCEG score recompute
  16. 2026-09-19 19:16 UTCVendor advisory
  17. 2026-09-19 19:16 UTCGHSA enrichment
  18. 2026-09-19 15:17 UTCVendor advisory
  19. 2026-09-19 15:17 UTCGHSA enrichment
  20. 2026-09-19 11:18 UTCVendor advisory
  21. 2026-09-19 11:18 UTCGHSA enrichment
  22. 2026-09-19 07:19 UTCVendor advisory
  23. 2026-09-19 07:19 UTCGHSA enrichment
  24. 2026-09-19 03:20 UTCVendor advisory
  25. 2026-09-19 03:20 UTCGHSA enrichment
  26. 2026-09-18 23:21 UTCEG score recompute
  27. 2026-09-18 23:21 UTCVendor advisory
  28. 2026-09-18 23:21 UTCGHSA enrichment
  29. 2026-09-18 19:27 UTCEPSS rescore
  30. 2026-09-18 19:22 UTCVendor advisory
  31. 2026-09-18 19:22 UTCGHSA enrichment
  32. 2026-09-18 19:20 UTCCISA KEV update
  33. 2026-09-18 15:23 UTCVendor advisory
  34. 2026-09-18 15:23 UTCGHSA enrichment
  35. 2026-09-18 14:15 UTCCISA KEV update
  36. 2026-09-18 11:24 UTCVendor advisory
  37. 2026-09-18 11:24 UTCGHSA enrichment
  38. 2026-09-18 07:25 UTCVendor advisory
  39. 2026-09-18 07:25 UTCGHSA enrichment
  40. 2026-09-18 03:26 UTCVendor advisory
  41. 2026-09-18 03:26 UTCGHSA enrichment
  42. 2026-09-17 23:27 UTCEG score recompute
  43. 2026-09-17 23:27 UTCVendor advisory
  44. 2026-09-17 23:27 UTCGHSA enrichment
  45. 2026-09-17 19:28 UTCVendor advisory
  46. 2026-09-17 19:28 UTCGHSA enrichment
  47. 2026-09-17 15:29 UTCVendor advisory
  48. 2026-09-17 15:29 UTCGHSA enrichment
  49. 2026-09-17 11:29 UTCVendor advisory
  50. 2026-09-17 11:29 UTCGHSA enrichment
  51. 2026-09-17 07:30 UTCVendor advisory
  52. 2026-09-17 07:30 UTCGHSA enrichment
  53. 2026-09-17 03:30 UTCVendor advisory
  54. 2026-09-17 03:30 UTCGHSA enrichment
  55. 2026-09-16 23:31 UTCVendor advisory
  56. 2026-09-16 23:31 UTCGHSA enrichment
  57. 2026-09-16 19:31 UTCVendor advisory
  58. 2026-09-16 19:31 UTCGHSA enrichment
  59. 2026-09-16 15:32 UTCEG score recompute
  60. 2026-09-16 15:32 UTCVendor advisory
  61. 2026-09-16 15:32 UTCGHSA enrichment
  62. 2026-09-16 14:10 UTCCISA KEV update
  63. 2026-09-16 14:07 UTCEPSS rescore
  64. 2026-09-16 11:33 UTCVendor advisory
  65. 2026-09-16 11:32 UTCGHSA enrichment
  66. 2026-09-16 07:31 UTCEG score recompute
  67. 2026-09-16 07:31 UTCVendor advisory
  68. 2026-09-16 07:31 UTCGHSA enrichment
  69. 2026-09-16 05:15 UTCEPSS rescore
  70. 2026-09-16 03:32 UTCVendor advisory
  71. 2026-09-16 03:32 UTCGHSA enrichment
  72. 2026-09-15 23:33 UTCVendor advisory
  73. 2026-09-15 23:33 UTCGHSA enrichment
  74. 2026-09-15 19:34 UTCVendor advisory
  75. 2026-09-15 19:34 UTCGHSA enrichment

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCfevar54/CVE-2026-21533_Scanner.py
    First seen Mar 9, 2026

    Este repositorio contiene una herramienta de **detección** para la vulnerabilidad CVE-2026-21533, una falla de gestión de privilegios en los Servicios de Escritorio Remoto (RDS) de Windows que podría permitir a un atacante local elevar sus privilegios a `SYSTEM`.

    Open source ↗

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2026-21533?
CVE-2026-21533 is a critical vulnerability published on February 10, 2026. Improper privilege management in Windows Remote Desktop allows an authorized attacker to elevate privileges locally.
When was CVE-2026-21533 disclosed?
CVE-2026-21533 was first published in the National Vulnerability Database on February 10, 2026, with the most recent update on August 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-21533 actively exploited?
Yes. CISA added CVE-2026-21533 to the Known Exploited Vulnerabilities catalog on February 10, 2026, affecting Microsoft Windows. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2026-21533?
CVE-2026-21533 has a CVSS v3 base score of 7.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2026-21533?
CVE-2026-21533 affects Microsoft Windows. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2026-21533?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-21533, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-21533

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