CVE-2021-27085

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 2021-11-03), 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 — 4 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictMitigate nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 5.4%CVSS: 8.8Exploit: cisa kev · ssvc activeExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

Internet Explorer Remote Code Execution Vulnerability

CVSS v3
8.8
EG Score
9.0CRITICALhigh confidence
EG Risk
81
EG Risk 81/100CISA SSVC

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%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines at low or medium mission impact and sooner than that at high; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
EPSS PROB
5.4%
EPSS %ILE
92nd
KEV
⚠ Exploited

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines at low or medium mission impact and sooner than that at high; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

Exploitation active (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

March 11, 2021

Last Modified

August 19, 2026

Advisory Details (2)

Auto-updated Jun 2, 2026
⚠️ Active exploitation confirmed. Fix referenced — no release confirmed yet. Sources: microsoft, cisa.
cisa🔴 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-2021-27085
microsoftMentions a patch (unverified)

Security Update Guide - Microsoft Security Response Center

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

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-27085

Vendor Advisories for CVE-2021-27085(2)

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

Data Freshness Timeline

(refreshed 105× in last 7d / 432× 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 1,802 total refreshes for this CVE.

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

Frequently asked(6)

What is CVE-2021-27085?
CVE-2021-27085 is a critical vulnerability published on March 11, 2021. Internet Explorer Remote Code Execution Vulnerability
When was CVE-2021-27085 disclosed?
CVE-2021-27085 was first published on March 11, 2021, 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-2021-27085 actively exploited?
Yes. CISA added CVE-2021-27085 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Microsoft Internet Explorer. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate attention. A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
What is the CVSS score of CVE-2021-27085?
CVE-2021-27085 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 (CRITICAL).
Which products are affected by CVE-2021-27085?
CVE-2021-27085 affects Microsoft Internet Explorer.
How do I remediate CVE-2021-27085?
A fix for CVE-2021-27085 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation. The vendor advisories EchelonGraph has for CVE-2021-27085 are linked in the Vendor Advisories panel on this page.

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