CVE-2021-34448

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 — 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: 40%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.

Scripting Engine Memory Corruption Vulnerability

CVSS v3
8.8
EG Score
9.0(high)
EG Risk
96(Act)
EG Risk 96/100SSVC: Act

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%
Automatability100% × 15%
Action: Fix now — active exploitation, automatable, high impact.
EPSS PROB
40%
EPSS %ILE
99%
KEV
⚠ Exploited

Published

July 16, 2021

Last Modified

August 10, 2026

Advisory Details (2)

Auto-updated Jun 11, 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-2021-34448
microsoft Patch Available

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-2021-34448

Vendor Advisories for CVE-2021-34448(1)

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.

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 110× in last 7d / 448× 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 1,682 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2021-34448?
CVE-2021-34448 is a critical vulnerability published on July 16, 2021. Scripting Engine Memory Corruption Vulnerability
When was CVE-2021-34448 disclosed?
CVE-2021-34448 was first published in the National Vulnerability Database on July 16, 2021, with the most recent update on August 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-34448 actively exploited?
Yes. CISA added CVE-2021-34448 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Microsoft Windows. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-34448?
CVE-2021-34448 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-2021-34448?
CVE-2021-34448 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-2021-34448?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-34448, 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-2021-34448

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