CVE-2026-21256
Published: 10 February 2026
Summary
CVE-2026-21256 is a high-severity Command Injection (CWE-77) vulnerability in Microsoft Visual Studio 2022. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked at the 14.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
This vulnerability is AI-related — categorised as Enterprise AI Assistants.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly remediates the command injection vulnerability by requiring timely identification, testing, and application of patches for GitHub Copilot and Visual Studio as provided by MSRC.
Prevents command injection by implementing input validation mechanisms to neutralize special elements before use in commands within the affected applications.
Mitigates the impact of successful command injection leading to arbitrary code execution through memory protection safeguards like DEP and ASLR.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Command injection (CWE-77/94) directly enables arbitrary command execution via T1059; network delivery with UI trigger maps to client-side exploitation T1203.
NVD Description
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.
Deeper analysisAI
CVE-2026-21256, published on 2026-02-10, is an improper neutralization of special elements used in a command, resulting in command injection (CWE-77, CWE-94). This vulnerability affects GitHub Copilot and Visual Studio, enabling an unauthorized attacker to execute code over a network. It carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H), indicating high severity due to network accessibility, low attack complexity, and significant impacts.
An unauthorized attacker with no required privileges can exploit the vulnerability remotely over the network, though it requires user interaction to trigger. Successful exploitation allows arbitrary code execution on the affected system, compromising confidentiality, integrity, and availability to a high degree.
The Microsoft Security Response Center (MSRC) provides an update guide for CVE-2026-21256 at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21256, which details mitigation strategies and available patches.
Details
- CWE(s)
Affected Products
AI Security AnalysisAI
- AI Category
- Enterprise AI Assistants
- Risk Domain
- N/A
- OWASP Top 10 for LLMs 2025
- None mapped
- Classification Reason
- Matched keywords: copilot