# CVE-2026-21523: GitHub Copilot and Visual Studio Code Remote Code Execution Vulnerability

> An authorized attacker can execute code via a race condition in GitHub Copilot and Visual Studio Code.

- **Severity:** High 8.0 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 10 Feb 2026
- **Updated:** 19 Aug 2026

## What is CVE-2026-21523?

CVE-2026-21523 is a high-severity vulnerability in Microsoft Visual Studio Code, published on 10 Feb 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Time-of-check time-of-use (toctou) race condition in GitHub Copilot and Visual Studio allows an authorized attacker to execute code over a network.

Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2026-21523?

It affects 1 product.


Products: Microsoft Visual Studio Code.

## How do I fix CVE-2026-21523?

No fix has been published for CVE-2026-21523 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-21523 being exploited?

There is no known exploitation of CVE-2026-21523 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Visual Studio Code

- [CVE-2026-81376](https://insights.sbomify.com/CVE-2026-81376/): Visual Studio Code Security Feature Bypass Vulnerability (critical 9.6)
- [CVE-2026-47281](https://insights.sbomify.com/CVE-2026-47281/): Visual Studio Code Elevation of Privilege Vulnerability (critical 9.6)
- [CVE-2026-78462](https://insights.sbomify.com/CVE-2026-78462/): Visual Studio Code Security Feature Bypass Vulnerability (high 8.8)
- [CVE-2026-59113](https://insights.sbomify.com/CVE-2026-59113/): Visual Studio Code Remote Code Execution Vulnerability (high 8.8)
- [CVE-2026-69320](https://insights.sbomify.com/CVE-2026-69320/): Visual Studio Code Remote Code Execution Vulnerability (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-21523 and fix it if it is affected.

What it is: CVE-2026-21523 is a high-severity vulnerability in Microsoft Visual Studio Code, published on 10 Feb 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-21523 in the wild and no public exploit code.

Affected product: Microsoft Visual Studio Code. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-21523/ (Markdown: https://insights.sbomify.com/CVE-2026-21523/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-21523
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-21523
- OSV: https://osv.dev/vulnerability/CVE-2026-21523

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-21523/
Summaries are generated and may contain mistakes; the official description above is the record.