CVE-2026-21256

HIGHNVD 8.88.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

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, GitHub Security Advisory, NVD CVSS v3
8.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.2%CVSS: 8.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
8.8HIGHmedium confidence
EG Risk
40
EG Risk 40/100

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 (value × EchelonGraph’s weight)
Severity88% × 45%
The EG Score, 8.8 of 10.
Exploitation1.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
1.2%
EPSS %ILE
67th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

February 10, 2026

Last Modified

August 19, 2026

Advisory Details (1)

Auto-updated Jun 7, 2026
Patch available. Sources: microsoft.
MicrosoftMentions a patch (unverified)

Security Update Guide - Microsoft Security Response Center

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21256

Vendor Advisories for CVE-2026-21256(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.

Data Freshness Timeline

(refreshed 11× in last 7d / 27× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 97 of 197 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 3 repeat rows among the latest 100 are merged into the row they repeat. The 100 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-16 16:41 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  2. 2026-10-15 16:31 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  3. 2026-10-14 16:32 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  4. 2026-10-13 16:33 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  5. 2026-10-12 16:33 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  6. 2026-10-12 16:23 UTCEG score recompute
  7. 2026-10-11 20:05 UTCEG score recompute
  8. 2026-10-11 17:18 UTCEG score recompute
  9. 2026-10-11 14:50 UTCEG score recompute
  10. 2026-10-11 13:48 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  11. 2026-10-10 19:59 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  12. 2026-10-09 20:06 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  13. 2026-10-08 17:11 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  14. 2026-10-07 23:47 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  15. 2026-10-06 15:17 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  16. 2026-10-05 17:42 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  17. 2026-10-04 23:21 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  18. 2026-10-01 19:49 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  19. 2026-09-30 15:03 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  20. 2026-09-29 15:21 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  21. 2026-09-28 13:51 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  22. 2026-09-27 13:47 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  23. 2026-09-26 15:58 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  24. 2026-09-26 00:26 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  25. 2026-09-24 14:03 UTCEPSS rescoreEPSS 1.1% · 65th percentile
Show 72 more
  1. 2026-09-20 20:15 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  2. 2026-09-18 19:27 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  3. 2026-09-16 14:07 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  4. 2026-09-16 05:15 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  5. 2026-09-13 16:47 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  6. 2026-09-12 15:01 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  7. 2026-09-11 14:52 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  8. 2026-09-10 09:34 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  9. 2026-09-08 22:00 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  10. 2026-09-07 16:01 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  11. 2026-09-06 13:47 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  12. 2026-09-04 05:06 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  13. 2026-09-02 14:11 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  14. 2026-09-01 13:53 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  15. 2026-09-01 04:39 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  16. 2026-08-30 19:17 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  17. 2026-08-30 01:22 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  18. 2026-08-28 21:41 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  19. 2026-08-27 14:25 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  20. 2026-08-26 14:46 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  21. 2026-08-25 13:48 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  22. 2026-08-23 00:19 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  23. 2026-08-21 23:49 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  24. 2026-08-20 22:55 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  25. 2026-08-19 17:54 UTCEG score recompute
  26. 2026-08-19 17:54 UTCVendor advisory
  27. 2026-08-19 17:54 UTCGHSA enrichmentGHSA-wr95-24gv-jx75 · GitHub severity HIGH · GitHub CVSS 8.8
  28. 2026-08-19 17:03 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  29. 2026-08-18 13:48 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  30. 2026-08-17 13:47 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  31. 2026-08-16 14:56 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  32. 2026-08-16 02:14 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  33. 2026-08-15 01:30 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  34. 2026-08-14 22:42 UTCVendor advisory
  35. 2026-08-14 22:42 UTCGHSA enrichmentGHSA-wr95-24gv-jx75 · GitHub severity HIGH · GitHub CVSS 8.8
  36. 2026-08-14 10:37 UTCEG score recompute
  37. 2026-08-14 10:37 UTCGHSA enrichmentGHSA-wr95-24gv-jx75 · GitHub severity HIGH · GitHub CVSS 8.8
  38. 2026-08-13 22:00 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  39. 2026-08-13 02:52 UTCEG score recompute
  40. 2026-08-13 02:52 UTCGHSA enrichmentGHSA-wr95-24gv-jx75 · GitHub severity HIGH · GitHub CVSS 8.8
  41. 2026-08-12 13:50 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  42. 2026-08-11 13:42 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  43. 2026-08-11 00:00 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  44. 2026-08-10 03:04 UTCVendor advisory
  45. 2026-08-10 03:04 UTCGHSA enrichmentGHSA-wr95-24gv-jx75 · GitHub severity HIGH · GitHub CVSS 8.8
  46. 2026-08-09 15:17 UTCEG score recompute
  47. 2026-08-09 15:17 UTCVendor advisory
  48. 2026-08-09 15:17 UTCGHSA enrichmentGHSA-wr95-24gv-jx75 · GitHub severity HIGH · GitHub CVSS 8.8
  49. 2026-08-09 13:46 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  50. 2026-08-08 16:37 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  51. 2026-08-08 09:43 UTCGHSA enrichmentGHSA-wr95-24gv-jx75 · GitHub severity HIGH · GitHub CVSS 8.8
  52. 2026-08-07 22:19 UTCEG score recompute
  53. 2026-08-07 22:19 UTCVendor advisory
  54. 2026-08-07 22:19 UTCGHSA enrichmentGHSA-wr95-24gv-jx75 · GitHub severity HIGH · GitHub CVSS 8.8
  55. 2026-08-06 13:46 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  56. 2026-08-06 04:05 UTCEG score recompute
  57. 2026-08-06 04:05 UTCVendor advisory
  58. 2026-08-06 04:05 UTCGHSA enrichmentGHSA-wr95-24gv-jx75 · GitHub severity HIGH · GitHub CVSS 8.8
  59. 2026-08-05 19:17 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  60. 2026-08-04 15:10 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  61. 2026-08-04 10:38 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  62. 2026-08-03 10:35 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  63. 2026-08-02 20:59 UTCEG score recompute
  64. 2026-08-02 20:59 UTCVendor advisory
  65. 2026-08-02 20:59 UTCGHSA enrichmentGHSA-wr95-24gv-jx75 · GitHub severity HIGH · GitHub CVSS 8.8
  66. 2026-08-02 02:26 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  67. 2026-08-01 04:15 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  68. 2026-07-30 01:30 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  69. 2026-07-27 14:13 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  70. 2026-07-26 14:54 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  71. 2026-07-25 14:17 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  72. 2026-07-24 14:17 UTCEPSS rescoreEPSS 1.1% · 62nd percentile

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-21256?
CVE-2026-21256 is a high-severity vulnerability; its CVE record was 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 made public?
CVE-2026-21256 was made public on February 10, 2026: that is the date its CVE record's CNA, Microsoft Corporation, gives for when the vulnerability was made public. The CVE record itself was published on February 10, 2026. EchelonGraph's copy of the record carries a last-modified date of August 19, 2026; the record at its source may have been updated since.
Is CVE-2026-21256 actively exploited?
CVE-2026-21256 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.2% probability of exploitation in the next 30 days (67th percentile of EPSS-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?
A fix for CVE-2026-21256 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-21256 are linked in the Vendor Advisories panel on this page.

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