High

Command Injection Privilege Escalation in GitHub Copilot and Visual Studio

IdentifiersCVE-2026-21257CWE-77· Improper Neutralization of Special…

CVE-2026-21257 is a command injection vulnerability affecting GitHub Copilot and Visual Studio. Microsoft describes the issue as improper neutralization of special elements used in a command, indicating attacker-controlled input is not safely sanitized before being incorporated into command execution. The vulnerability is classified as CWE-77. According to the available information, exploitation allows an authorized attacker to elevate privileges over a network, and user interaction is required. The published CVSS v3.1 vector is AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H, indicating low attack complexity, low privileges required, and high impact to confidentiality, integrity, and availability. Specific vulnerable functions, code paths, or feature workflows were not provided in the supplied content.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can allow an authorized attacker to achieve privilege escalation in the context of GitHub Copilot and Visual Studio over a network. Based on the CVSS vector, the resulting impact can be high across confidentiality, integrity, and availability, implying potential access to sensitive data, unauthorized modification of data or system state, and disruption of normal operation. The supplied content does not provide more granular post-exploitation details such as exact privilege level obtained or whether arbitrary command execution occurs as the elevated context.

Mitigation

If you can’t patch tonight, do this now.

No specific mitigation or workaround was provided in the supplied content. In the absence of a vendor workaround, the primary mitigation is prompt application of Microsoft's February 2026 security updates. Because exploitation requires an authorized attacker and user interaction, reducing unnecessary user privileges and limiting exposure of affected development environments may reduce risk, but the content does not document any official mitigation beyond patching.

Remediation

Patch, then assume compromise.

Microsoft released a security update for this vulnerability as part of the February 2026 security updates. Affected organizations should apply the relevant Microsoft patches for supported versions of GitHub Copilot and Visual Studio and verify successful installation through normal Microsoft update validation processes. No product-specific configuration changes or code-level remediation details were provided in the supplied content.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Microsoft CorporationGithub Copilotapplication

Microsoft CorporationVisual Studioapplication

Microsoft CorporationVisual Studio 2022application

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

10 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

10 SOURCESView more in app

nsfocus globalNews

Mar 4, 2026

Microsoft’s February Security Update of High-Risk Vulnerability Notice for Multiple Products - NSFOCUS, Inc., a global network and cyber security leader, protects enterprises and carriers from advanced cyber attacks.

A privilege escalation vulnerability affecting GitHub Copilot integration in Microsoft Visual Studio.

thecyberexpress com vulnerabilitiesNews

Feb 11, 2026

Microsoft Patch Tuesday February 2026 Fixes 6 Zero-Days

A vulnerability affecting GitHub Copilot and Visual Studio; specific impact type not provided in the content.

cyber security newsNews

Feb 10, 2026

Microsoft Patch Tuesday February 2026 - 54 Vulnerabilities Fixed, Including 6 Zero-days

An elevation of privilege vulnerability affecting GitHub Copilot and Visual Studio.

bleeping computerNews

Feb 10, 2026

Microsoft February 2026 Patch Tuesday fixes 6 zero-days, 58 flaws

An elevation of privilege vulnerability affecting GitHub Copilot and Visual Studio (no additional details provided in the content).

+2 more in the timeline

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity3

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-21257

NVD

nvd.nist.gov/vuln/detail/CVE-2026-21257

MITRE CWE · CWE-77

Improper Neutralization of Special Elements…

Vendor Advisory

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21257