CVE-2026-78449

HIGHPre-NVD 8.18.1—
EchelonGraph scoreHIGH confidence

Score 8.1 from GitHub Security Advisory (severity: HIGH) published 2026-09-08. a secondary CVSS source baseline 8.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
8.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.1Exploit: None knownExposed: 0

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

Use after free in Reliable Multicast Transport Driver (RMCAST) allows an unauthorized attacker to execute code over a network.

CVSS v3
8.1
EG Score
8.1(high)
EG Risk
37(Track)
EG Risk 37/100SSVC: 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
Severity81% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
51%
KEV
Not listed

Published

September 8, 2026

Last Modified

September 24, 2026

Advisory Details (1)

Auto-updated Sep 8, 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-2026-78449

Vendor Advisories for CVE-2026-78449(2)

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.

Data Freshness Timeline

(refreshed 55× in last 7d / 133× 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 133 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-78449?
CVE-2026-78449 is a high vulnerability published on September 8, 2026. Use after free in Reliable Multicast Transport Driver (RMCAST) allows an unauthorized attacker to execute code over a network.
When was CVE-2026-78449 disclosed?
CVE-2026-78449 was first published in the National Vulnerability Database on September 8, 2026, with the most recent update on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-78449 actively exploited?
CVE-2026-78449 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 48.6% of all scored CVEs.
What is the CVSS score of CVE-2026-78449?
CVE-2026-78449 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-78449?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-78449, 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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