MSRC_CVE-2026-21256

Vulnerability from csaf_microsoft - Published: 2026-02-10 08:00 - Updated: 2026-02-11 08:00
Summary
GitHub Copilot and Visual Studio Remote Code Execution Vulnerability

Notes

Additional Resources
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
Disclaimer
The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
Customer Action
Required. The vulnerability documented by this CVE requires customer action to resolve.
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{
  "document": {
    "acknowledgments": [
      {
        "names": [
          "\u003ca href=\"https://www.linkedin.com/in/tarek-nakkouch/\"\u003eNakkouch Tarek\u003c/a\u003e"
        ]
      }
    ],
    "aggregate_severity": {
      "namespace": "https://www.microsoft.com/en-us/msrc/security-update-severity-rating-system",
      "text": "Important"
    },
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      },
      {
        "category": "general",
        "text": "Required. The vulnerability documented by this CVE requires customer action to resolve.",
        "title": "Customer Action"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-21256 GitHub Copilot and Visual Studio Remote Code Execution Vulnerability - HTML",
        "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21256"
      },
      {
        "category": "self",
        "summary": "CVE-2026-21256 GitHub Copilot and Visual Studio Remote Code Execution Vulnerability - CSAF",
        "url": "https://msrc.microsoft.com/csaf/advisories/2026/msrc_cve-2026-21256.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Exploitability Index",
        "url": "https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "GitHub Copilot and Visual Studio Remote Code Execution Vulnerability",
    "tracking": {
      "current_release_date": "2026-02-11T08:00:00.000Z",
      "generator": {
        "date": "2026-02-11T16:16:27.618Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-21256",
      "initial_release_date": "2026-02-10T08:00:00.000Z",
      "revision_history": [
        {
          "date": "2026-02-10T08:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2026-02-11T08:00:00.000Z",
          "legacy_version": "1.1",
          "number": "2",
          "summary": "Changes made to the security updates links and information.  This is an informational change only."
        }
      ],
      "status": "final",
      "version": "2"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c17.14.26",
            "product": {
              "name": "Microsoft Visual Studio 2022 version 17.14 \u003c17.14.26",
              "product_id": "2"
            }
          },
          {
            "category": "product_version",
            "name": "17.14.26",
            "product": {
              "name": "Microsoft Visual Studio 2022 version 17.14 17.14.26",
              "product_id": "16767"
            }
          }
        ],
        "category": "product_name",
        "name": "Microsoft Visual Studio 2022 version 17.14"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c18.3.0",
            "product": {
              "name": "Microsoft Visual Studio 2022 version 18.3 \u003c18.3.0",
              "product_id": "1"
            }
          },
          {
            "category": "product_version",
            "name": "18.3.0",
            "product": {
              "name": "Microsoft Visual Studio 2022 version 18.3 18.3.0",
              "product_id": "20843"
            }
          }
        ],
        "category": "product_name",
        "name": "Microsoft Visual Studio 2022 version 18.3"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-21256",
      "cwe": {
        "id": "CWE-77",
        "name": "Improper Neutralization of Special Elements used in a Command (\u0027Command Injection\u0027)"
      },
      "notes": [
        {
          "category": "general",
          "text": "Microsoft",
          "title": "Assigning CNA"
        },
        {
          "category": "faq",
          "text": "The AV:N rating indicates the vulnerability is exploitable over the network, meaning an attacker can deliver a malicious prompt remotely without prior access, while UI:R means a user must interact with Copilot for exploitation to occur. Due to prompt injection, the system is coerced into executing attacker-controlled instructions, which can escalate into remote code execution (RCE) when the compromised prompt causes backend components or integrated tools to run unintended commands.",
          "title": "How could an attacker exploit this vulnerability?"
        }
      ],
      "product_status": {
        "fixed": [
          "16767",
          "20843"
        ],
        "known_affected": [
          "1",
          "2"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-21256 GitHub Copilot and Visual Studio Remote Code Execution Vulnerability - HTML",
          "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21256"
        },
        {
          "category": "self",
          "summary": "CVE-2026-21256 GitHub Copilot and Visual Studio Remote Code Execution Vulnerability - CSAF",
          "url": "https://msrc.microsoft.com/csaf/advisories/2026/msrc_cve-2026-21256.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-02-10T08:00:00.000Z",
          "details": "17.14.26:Security Update:https://learn.microsoft.com/en-us/visualstudio/releases/2022/release-notes",
          "product_ids": [
            "2"
          ],
          "url": "https://learn.microsoft.com/en-us/visualstudio/releases/2022/release-notes"
        },
        {
          "category": "vendor_fix",
          "date": "2026-02-10T08:00:00.000Z",
          "details": "18.3.0:Security Update:https://learn.microsoft.com/en-us/visualstudio/releases/2026/release-notes",
          "product_ids": [
            "1"
          ],
          "url": "https://learn.microsoft.com/en-us/visualstudio/releases/2026/release-notes"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "environmentalsScore": 0.0,
            "exploitCodeMaturity": "UNPROVEN",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "remediationLevel": "OFFICIAL_FIX",
            "reportConfidence": "CONFIRMED",
            "scope": "UNCHANGED",
            "temporalScore": 7.7,
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C",
            "version": "3.1"
          },
          "products": [
            "1",
            "2"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Remote Code Execution"
        },
        {
          "category": "exploit_status",
          "details": "Publicly Disclosed:No;Exploited:No;Latest Software Release:Exploitation Less Likely"
        }
      ],
      "title": "GitHub Copilot and Visual Studio Remote Code Execution Vulnerability"
    }
  ]
}


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Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.