CVE-2026-21256

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-02-10. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.8Exploit: None knownExposed: 0

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

Improper neutralization of special elements used in a command ('command injection') in GitHub Copilot and Visual Studio allows an unauthorized attacker to execute code over a network.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: 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
Severity88% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
63%
KEV
Not listed

Published

February 10, 2026

Last Modified

August 19, 2026

Advisory Details (1)

Auto-updated Jun 7, 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-2026-21256

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 7× in last 7d / 51× 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 160 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-21256?
CVE-2026-21256 is a high vulnerability published on February 10, 2026. Improper neutralization of special elements used in a command ('command injection') in GitHub Copilot and Visual Studio allows an unauthorized attacker to execute code over a network.
When was CVE-2026-21256 disclosed?
CVE-2026-21256 was first published in the National Vulnerability Database on February 10, 2026, 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-2026-21256 actively exploited?
CVE-2026-21256 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 36.6% of all scored CVEs.
What is the CVSS score of CVE-2026-21256?
CVE-2026-21256 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-21256?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-21256, 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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