CVE-2026-62815

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-11. The CNA's CVSS baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
Trending — 3 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.0%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
59
EG Risk 59/100CISA 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
Severity98% × 45%
Exploitation1% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
1.0%
EPSS %ILE
60th
KEV
Not listed

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

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (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

August 11, 2026

Last Modified

September 29, 2026

Advisory Details (1)

Auto-updated Sep 29, 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-2026-62815

Vendor Advisories for CVE-2026-62815(2)

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

Affected Packages

(2 across 1 ecosystem)
NuGet(2)
PackageVulnerable rangeFix by version rangeDependents
Microsoft.Native.Quic.MsQuic.OpenSSL1.8.0
  • 2.5.3 up to 2.5.10: fixed in 2.5.10
  • every version up to 2.4.19: fixed in 2.4.19
—
Microsoft.Native.Quic.MsQuic.Schannel1.8.0
  • 2.5.3 up to 2.5.10: fixed in 2.5.10
  • every version up to 2.4.19: fixed in 2.4.19
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 30× in last 7d / 170× 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 541 total refreshes for this CVE.

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

Related CVEs(same product + same CWE)

Same product

2 shown

NuGet:Microsoft.Native.Quic.MsQuic.OpenSSL

Frequently asked(5)

What is CVE-2026-62815?
CVE-2026-62815 is a critical vulnerability published on August 11, 2026. Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.
When was CVE-2026-62815 disclosed?
CVE-2026-62815 was first published on August 11, 2026, with the most recent update on September 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-62815 actively exploited?
CVE-2026-62815 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.0% probability of exploitation in the next 30 days (60th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-62815?
CVE-2026-62815 has a CVSS base score of 9.8 (the CNA's own assessment, by microsoft; NVD's own analysis pending).
How do I remediate CVE-2026-62815?
A fix for CVE-2026-62815 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-62815 are linked in the Vendor Advisories panel on this page.

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