CVE-2021-42306

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2021-11-25. NVD baseline CVSS 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 3%CVSS: 6.5Exploit: None knownExposed: 0

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

An information disclosure vulnerability manifests when a user or an application uploads unprotected private key data as part of an authentication certificate keyCredential  on an Azure AD Application or Service Principal (which is not recommended). This vulnerability allows a user or service in the tenant with application read access to read the private key data that was added to the application. Azure AD addressed this vulnerability by preventing disclosure of any private key values added to the application. Microsoft has identified services that could manifest this vulnerability, and steps that customers should take to be protected. Refer to the FAQ section for more information. For more details on this issue, please refer to the MSRC Blog Entry.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: Track

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
Severity65% × 45%
Exploitation3% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
3%
EPSS %ILE
87%
KEV
Not listed

Published

November 24, 2021

Last Modified

August 19, 2026

Advisory Details (1)

Auto-updated Aug 19, 2026
Patch available. Sources: microsoft.
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-2021-42306

Vendor Advisories for CVE-2021-42306(1)

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

Weakness Classification(2)

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 6× in last 7d / 33× 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 150 total refreshes for this CVE.

  1. 2026-09-07 15:58 UTCEPSS rescore
  2. 2026-09-06 13:45 UTCEPSS rescore
  3. 2026-09-05 15:25 UTCEPSS rescore
  4. 2026-09-04 13:57 UTCEPSS rescore
  5. 2026-09-04 05:03 UTCEPSS rescore
  6. 2026-09-02 14:09 UTCEPSS rescore
  7. 2026-09-01 13:50 UTCEPSS rescore
  8. 2026-09-01 03:33 UTCEPSS rescore
  9. 2026-08-30 19:14 UTCEPSS rescore
  10. 2026-08-30 19:14 UTCEPSS rescore
  11. 2026-08-30 01:19 UTCEPSS rescore
  12. 2026-08-28 21:37 UTCEPSS rescore
  13. 2026-08-27 14:22 UTCEPSS rescore
  14. 2026-08-26 14:43 UTCEPSS rescore
  15. 2026-08-25 13:46 UTCEPSS rescore
  16. 2026-08-24 14:13 UTCEPSS rescore
  17. 2026-08-23 00:16 UTCEPSS rescore
  18. 2026-08-21 23:46 UTCEPSS rescore
  19. 2026-08-20 22:52 UTCEPSS rescore
  20. 2026-08-20 22:52 UTCEPSS rescore
  21. 2026-08-19 18:05 UTCEG score recompute▼ 1.60
  22. 2026-08-19 18:05 UTCVendor advisory
  23. 2026-08-19 18:05 UTCGHSA enrichment
  24. 2026-08-19 17:20 UTCNVD updateCVSS v3 → 6.5 · severity → MEDIUM
  25. 2026-08-19 17:01 UTCEPSS rescore
Show 75 more
  1. 2026-08-18 13:45 UTCEPSS rescore
  2. 2026-08-17 13:44 UTCEPSS rescore
  3. 2026-08-16 14:53 UTCEPSS rescore
  4. 2026-08-16 02:11 UTCEPSS rescore
  5. 2026-08-15 01:27 UTCEPSS rescore
  6. 2026-08-13 21:57 UTCEPSS rescore
  7. 2026-08-12 13:48 UTCEPSS rescore
  8. 2026-08-11 13:38 UTCEPSS rescore
  9. 2026-08-08 16:33 UTCEPSS rescore
  10. 2026-08-07 16:24 UTCEPSS rescore
  11. 2026-08-06 13:44 UTCEPSS rescore
  12. 2026-08-05 19:14 UTCEPSS rescore
  13. 2026-08-04 10:34 UTCEPSS rescore
  14. 2026-08-03 10:33 UTCEPSS rescore
  15. 2026-08-02 02:24 UTCEPSS rescore
  16. 2026-08-01 04:13 UTCEPSS rescore
  17. 2026-07-30 16:25 UTCEPSS rescore
  18. 2026-07-30 01:28 UTCEPSS rescore
  19. 2026-07-28 15:33 UTCEPSS rescore
  20. 2026-07-26 14:52 UTCEPSS rescore
  21. 2026-07-26 14:52 UTCEPSS rescore
  22. 2026-07-25 14:15 UTCEPSS rescore
  23. 2026-07-24 14:15 UTCEPSS rescore
  24. 2026-07-23 14:16 UTCEPSS rescore
  25. 2026-07-23 02:04 UTCEG score recompute
  26. 2026-07-22 22:51 UTCEG score recompute▲ 1.60
  27. 2026-07-22 14:06 UTCEPSS rescore
  28. 2026-07-21 15:22 UTCEPSS rescore
  29. 2026-07-21 15:22 UTCEPSS rescore
  30. 2026-07-20 17:05 UTCEPSS rescore
  31. 2026-07-19 14:29 UTCEPSS rescore
  32. 2026-07-19 02:27 UTCEPSS rescore
  33. 2026-07-18 10:02 UTCEPSS rescore
  34. 2026-07-18 10:02 UTCEPSS rescore
  35. 2026-07-16 17:00 UTCEPSS rescore
  36. 2026-07-16 17:00 UTCEPSS rescore
  37. 2026-07-15 16:55 UTCEPSS rescore
  38. 2026-07-15 16:55 UTCEPSS rescore
  39. 2026-07-15 01:58 UTCEPSS rescore
  40. 2026-07-13 22:27 UTCEPSS rescore
  41. 2026-07-13 22:27 UTCEPSS rescore
  42. 2026-07-13 06:11 UTCEPSS rescore
  43. 2026-07-13 06:11 UTCEPSS rescore
  44. 2026-07-12 05:44 UTCEPSS rescore
  45. 2026-07-11 08:25 UTCEPSS rescore
  46. 2026-07-11 08:25 UTCEPSS rescore
  47. 2026-07-09 19:07 UTCEPSS rescore
  48. 2026-07-08 15:12 UTCEPSS rescore
  49. 2026-07-07 13:43 UTCEPSS rescore
  50. 2026-07-06 16:25 UTCEPSS rescore
  51. 2026-07-06 16:25 UTCEPSS rescore
  52. 2026-07-06 02:21 UTCEPSS rescore
  53. 2026-07-06 02:21 UTCEPSS rescore
  54. 2026-07-05 02:28 UTCEPSS rescore
  55. 2026-07-05 02:28 UTCEPSS rescore
  56. 2026-07-04 06:29 UTCEPSS rescore
  57. 2026-07-04 06:29 UTCEPSS rescore
  58. 2026-07-02 16:57 UTCEPSS rescore
  59. 2026-07-01 15:04 UTCEPSS rescore
  60. 2026-06-30 23:20 UTCEPSS rescore
  61. 2026-06-30 23:20 UTCEPSS rescore
  62. 2026-06-29 14:04 UTCEPSS rescore
  63. 2026-06-28 14:05 UTCEPSS rescore
  64. 2026-06-28 04:54 UTCEPSS rescore
  65. 2026-06-28 04:54 UTCEPSS rescore
  66. 2026-06-27 03:06 UTCEPSS rescore
  67. 2026-06-27 03:06 UTCEPSS rescore
  68. 2026-06-25 13:48 UTCEPSS rescore
  69. 2026-06-25 13:48 UTCEPSS rescore
  70. 2026-06-24 14:03 UTCEPSS rescore
  71. 2026-06-24 14:03 UTCEPSS rescore
  72. 2026-06-22 14:24 UTCEPSS rescore
  73. 2026-06-21 14:55 UTCEPSS rescore
  74. 2026-06-21 01:58 UTCEPSS rescore
  75. 2026-06-21 01:58 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-42306?
CVE-2021-42306 is a medium vulnerability published on November 24, 2021. An information disclosure vulnerability manifests when a user or an application uploads unprotected private key data as part of an authentication certificate keyCredential on an Azure AD Application or Service Principal (which is not recommended). This vulnerability allows a user or service in the…
When was CVE-2021-42306 disclosed?
CVE-2021-42306 was first published in the National Vulnerability Database on November 24, 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-2021-42306 actively exploited?
CVE-2021-42306 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3% probability of exploitation in the next 30 days, which ranks it in the top 13.1% of all scored CVEs.
What is the CVSS score of CVE-2021-42306?
CVE-2021-42306 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2021-42306?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-42306, 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.

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