CVE-2026-21256
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedImproper 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA command injection vulnerability in GitHub Copilot and Visual Studio allows an attacker to execute arbitrary code over a network by injecting special characters into commands. The vulnerability stems from improper neutralization of special elements in command execution contexts.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 17.14.0, < 17.14.26CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm Visual Studio 2022 installationCheck for Visual Studio 2022 installation by looking in Program Files\Microsoft Visual Studio\2022 or via the 'Help > About Microsoft Visual Studio' dialog in the IDEAffected if Visual Studio 2022 is not installed on the system
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Determine the installed Visual Studio 2022 versionOpen Visual Studio 2022, go to Help > About Microsoft Visual Studio, and note the version number shown (e.g., 17.14.x)Affected if The installed version is 17.14.0 or higher, but lower than 17.14.26
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Verify if GitHub Copilot extension is enabledIn Visual Studio 2022, go to Extensions > Manage Extensions > Installed, or check for Copilot icon in the IDE status bar, to see if the Copilot extension is installed and activeAffected if GitHub Copilot for Visual Studio is installed and enabled
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Check for network-accessible IDE componentsReview Visual Studio 2022 installed workloads and any running services that may expose IDE functionality over the network (check Task Manager for related processes)Affected if Network-accessible IDE components or Copilot network services are active and accessible
The environment is affected if Visual Studio 2022 version 17.14.0 through 17.14.25 is installed with GitHub Copilot enabled and network-accessible IDE components are active.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped17.14.26
Apply vendor-supplied patches when available; until then, restrict network access to affected IDE components and avoid using Copilot features with untrusted input sources.
Visual Studio 2022 version 17.14.26 or later
- Close Visual Studio 2022 completely before updating
- Open the Visual Studio Installer application
- Click the Update button to check for available updates
- Install the update which should include version 17.14.26 or later
- After installation completes, launch Visual Studio 2022 and verify the version via Help > About Microsoft Visual Studio shows 17.14.26 or higher
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA8.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $12,352.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-21256 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-21256 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data