CVE-2026-8863

HIGHPre-NVD 7.87.8—
EchelonGraph scoreHIGH confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-06-09. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 4 sources updated this week
7.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.8Exploit: NoneExposed: 0

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

Multiple Microsoft-sigend UEFI SHIM bootloaders are vulnerable to SecureBoot bypass. An attacker with administrative privileges or the ability to modify the boot process could use one of the vulnerable shim bootloaders to bypass Secure Boot protections and execute arbitrary code before the operating system loads. Specific UEFI DBX update is required to block these vulnerable boot loaders.

CVSS v3
7.8
EG Score
7.8(high)
EPSS
0.9%
KEV
Not listed

Published

June 9, 2026

Last Modified

June 10, 2026

Advisory Details (3)

Auto-updated Jun 9, 2026
Patch available. Sources: cert, microsoft.
cert

VU#616257 - Microsoft-signed UEFI shim bootloaders vulnerable to Secure Boot bypass

https://www.kb.cert.org/vuls/id/616257
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-2026-8863
cert

VU#616257 - Microsoft-signed UEFI shim bootloaders vulnerable to Secure Boot bypass

https://kb.cert.org/vuls/id/616257

Vendor Advisories for CVE-2026-8863(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 41× in last 7d / 161× 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 161 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-8863?
CVE-2026-8863 is a high vulnerability published on June 9, 2026. Multiple Microsoft-sigend UEFI SHIM bootloaders are vulnerable to SecureBoot bypass. An attacker with administrative privileges or the ability to modify the boot process could use one of the vulnerable shim bootloaders to bypass Secure Boot protections and execute arbitrary code before the…
When was CVE-2026-8863 disclosed?
CVE-2026-8863 was first published in the National Vulnerability Database on June 9, 2026, with the most recent update on June 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8863 actively exploited?
CVE-2026-8863 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-8863?
CVE-2026-8863 has a CVSS v3.1 base score of 7.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-8863?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8863, 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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