CVE-2026-21513

CRITICALNVD 8.89.0▲
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 8.8 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: 15%CVSS: 8.8Exploit: cisa kev · ssvc active · epss top5pctExposed: 0

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

Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network.

CVSS v3
8.8
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
15%
EPSS %ILE
96%
KEV
⚠ Exploited

Published

February 10, 2026

Last Modified

June 17, 2026

Advisory Details (4)

Auto-updated Jun 1, 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-2026-21513
generic🔴 Active Exploitation

CVE-2026-21513 Mitigation Script - Security Feature Bypass Vulnerability in MSHTML Framework - vsociety

https://www.vicarius.io/vsociety/posts/cve-2026-21513-mitigation-script-security-feature-bypass-vulnerability-in-mshtml-framework
generic🔴 Active Exploitation

CVE-2026-21513 Detection Script - Security Feature Bypass Vulnerability in MSHTML Framework - vsociety

https://www.vicarius.io/vsociety/posts/cve-2026-21513-detection-script-security-feature-bypass-vulnerability-in-mshtml-framework
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-2026-21513

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 69× in last 7d / 402× 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 800 total refreshes for this CVE.

  1. 2026-07-28 02:03 UTCVendor advisory
  2. 2026-07-28 02:03 UTCGHSA enrichment
  3. 2026-07-27 22:21 UTCVendor advisory
  4. 2026-07-27 22:20 UTCGHSA enrichment
  5. 2026-07-27 19:24 UTCCISA KEV update
  6. 2026-07-27 18:37 UTCVendor advisory
  7. 2026-07-27 18:37 UTCGHSA enrichment
  8. 2026-07-27 17:17 UTCCISA KEV update
  9. 2026-07-27 14:53 UTCVendor advisory
  10. 2026-07-27 14:53 UTCGHSA enrichment
  11. 2026-07-27 11:10 UTCGHSA enrichment
  12. 2026-07-27 07:28 UTCVendor advisory
  13. 2026-07-27 07:27 UTCGHSA enrichment
  14. 2026-07-27 03:44 UTCVendor advisory
  15. 2026-07-27 03:43 UTCGHSA enrichment
  16. 2026-07-27 00:00 UTCVendor advisory
  17. 2026-07-27 00:00 UTCGHSA enrichment
  18. 2026-07-26 20:17 UTCVendor advisory
  19. 2026-07-26 20:17 UTCGHSA enrichment
  20. 2026-07-26 16:32 UTCEG score recompute
  21. 2026-07-26 16:32 UTCVendor advisory
  22. 2026-07-26 16:32 UTCGHSA enrichment
  23. 2026-07-26 14:54 UTCEPSS rescore
  24. 2026-07-26 14:54 UTCEPSS rescore
  25. 2026-07-26 12:48 UTCEG score recompute
Show 75 more
  1. 2026-07-26 12:48 UTCVendor advisory
  2. 2026-07-26 12:48 UTCGHSA enrichment
  3. 2026-07-26 09:05 UTCVendor advisory
  4. 2026-07-26 09:05 UTCGHSA enrichment
  5. 2026-07-26 05:22 UTCVendor advisory
  6. 2026-07-26 05:21 UTCGHSA enrichment
  7. 2026-07-26 01:38 UTCEG score recompute
  8. 2026-07-26 01:38 UTCVendor advisory
  9. 2026-07-26 01:38 UTCGHSA enrichment
  10. 2026-07-25 14:17 UTCEPSS rescore
  11. 2026-07-25 14:17 UTCEPSS rescore
  12. 2026-07-24 14:17 UTCEPSS rescore
  13. 2026-07-23 14:18 UTCEPSS rescore
  14. 2026-07-23 14:18 UTCEPSS rescore
  15. 2026-07-23 03:06 UTCEG score recompute
  16. 2026-07-22 21:49 UTCEG score recompute
  17. 2026-07-22 21:49 UTCVendor advisory
  18. 2026-07-22 21:49 UTCGHSA enrichment
  19. 2026-07-22 19:40 UTCCISA KEV update
  20. 2026-07-22 18:05 UTCGHSA enrichment
  21. 2026-07-22 14:22 UTCEG score recompute
  22. 2026-07-22 14:22 UTCVendor advisory
  23. 2026-07-22 14:21 UTCGHSA enrichment
  24. 2026-07-22 14:08 UTCEPSS rescore
  25. 2026-07-22 10:39 UTCVendor advisory
  26. 2026-07-22 10:39 UTCGHSA enrichment
  27. 2026-07-22 06:56 UTCVendor advisory
  28. 2026-07-22 06:56 UTCGHSA enrichment
  29. 2026-07-22 03:12 UTCVendor advisory
  30. 2026-07-22 03:12 UTCGHSA enrichment
  31. 2026-07-21 23:29 UTCVendor advisory
  32. 2026-07-21 23:29 UTCGHSA enrichment
  33. 2026-07-21 19:45 UTCVendor advisory
  34. 2026-07-21 19:45 UTCGHSA enrichment
  35. 2026-07-21 16:01 UTCEG score recompute
  36. 2026-07-21 16:01 UTCVendor advisory
  37. 2026-07-21 16:01 UTCGHSA enrichment
  38. 2026-07-21 15:24 UTCEPSS rescore
  39. 2026-07-21 15:24 UTCEPSS rescore
  40. 2026-07-21 14:37 UTCCISA KEV update
  41. 2026-07-21 12:16 UTCVendor advisory
  42. 2026-07-21 12:16 UTCGHSA enrichment
  43. 2026-07-21 08:33 UTCVendor advisory
  44. 2026-07-21 08:33 UTCGHSA enrichment
  45. 2026-07-21 04:50 UTCVendor advisory
  46. 2026-07-21 04:50 UTCGHSA enrichment
  47. 2026-07-21 01:07 UTCVendor advisory
  48. 2026-07-21 01:07 UTCGHSA enrichment
  49. 2026-07-20 21:24 UTCVendor advisory
  50. 2026-07-20 21:24 UTCGHSA enrichment
  51. 2026-07-20 17:41 UTCEG score recompute
  52. 2026-07-20 17:41 UTCVendor advisory
  53. 2026-07-20 17:41 UTCGHSA enrichment
  54. 2026-07-20 17:08 UTCEPSS rescore
  55. 2026-07-20 13:58 UTCGHSA enrichment
  56. 2026-07-20 10:15 UTCGHSA enrichment
  57. 2026-07-20 06:33 UTCVendor advisory
  58. 2026-07-20 06:32 UTCGHSA enrichment
  59. 2026-07-20 02:26 UTCVendor advisory
  60. 2026-07-20 02:26 UTCGHSA enrichment
  61. 2026-07-19 22:43 UTCVendor advisory
  62. 2026-07-19 22:43 UTCGHSA enrichment
  63. 2026-07-19 19:00 UTCVendor advisory
  64. 2026-07-19 19:00 UTCGHSA enrichment
  65. 2026-07-19 15:17 UTCEG score recompute
  66. 2026-07-19 15:17 UTCVendor advisory
  67. 2026-07-19 15:17 UTCGHSA enrichment
  68. 2026-07-19 14:31 UTCEPSS rescore
  69. 2026-07-19 14:31 UTCEPSS rescore
  70. 2026-07-19 11:34 UTCVendor advisory
  71. 2026-07-19 11:34 UTCGHSA enrichment
  72. 2026-07-19 07:51 UTCVendor advisory
  73. 2026-07-19 07:51 UTCGHSA enrichment
  74. 2026-07-19 04:08 UTCVendor advisory
  75. 2026-07-19 04:08 UTCGHSA enrichment

Frequently asked(6)

What is CVE-2026-21513?
CVE-2026-21513 is a critical vulnerability published on February 10, 2026. Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network.
When was CVE-2026-21513 disclosed?
CVE-2026-21513 was first published in the National Vulnerability Database on February 10, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-21513 actively exploited?
Yes. CISA added CVE-2026-21513 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-2026-21513?
CVE-2026-21513 has a CVSS v3 base score of 8.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2026-21513?
CVE-2026-21513 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-2026-21513?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-21513, 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

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