CVE-2021-27059

CRITICALNVD 6.59.0▲
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 6.5 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: 6.1%CVSS: 6.5Exploit: 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).

Microsoft Office Remote Code Execution Vulnerability

CVSS v3
6.5
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, Attend at medium and Act at high mission impact.
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, sooner than that at medium and as soon as possible at high mission impact; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
EPSS PROB
6.1%
EPSS %ILE
93rd
KEV
⚠ Exploited

CISA SSVCTrack at low, Attend at medium and Act at high mission impact.

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, sooner than that at medium and as soon as possible at high mission impact; 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 total (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 4, 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-2021-27059
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-2021-27059

Vendor Advisories for CVE-2021-27059(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 96× 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 1,733 total refreshes for this CVE.

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

Frequently asked(6)

What is CVE-2021-27059?
CVE-2021-27059 is a critical vulnerability published on March 11, 2021. Microsoft Office Remote Code Execution Vulnerability
When was CVE-2021-27059 disclosed?
CVE-2021-27059 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-2021-27059 actively exploited?
Yes. CISA added CVE-2021-27059 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Microsoft Office. 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-2021-27059?
CVE-2021-27059 has a CVSS v3 base score of 6.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0 (CRITICAL).
Which products are affected by CVE-2021-27059?
CVE-2021-27059 affects Microsoft Office.
How do I remediate CVE-2021-27059?
A fix for CVE-2021-27059 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-2021-27059 are linked in the Vendor Advisories panel on this page.

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