# GitHub Copilot for JetBrains: a command injection leaks local data

> CVE-2026-83953 is a command injection flaw in the GitHub Copilot plugin for JetBrains IDEs, fixed in plugin version 1.17.0-251.

- **Severity:** Medium: Real and reproducible, but needs unusual setup, user help or a narrow audience. Plan a fix.
- **Category:** Vulnerability
- **Published by:** Microsoft
- **Disclosed:** 2026-11-10
- **CVE:** CVE-2026-83953
- **CVSS:** 5.5
- **Affects:** GitHub Copilot for JetBrains
- **Research by:** Microsoft Security Response Center
- **Primary source:** https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83953
- **Page:** https://theinjection.dev/items/github-copilot-jetbrains-cve-2026-83953/

Microsoft published CVE-2026-83953 on 10 November 2026, a command injection flaw in the GitHub Copilot plugin for JetBrains IDEs that lets a local attacker with low privileges read information. Plugin version 1.17.0-251 fixes it.

## What happened

Microsoft published CVE-2026-83953 on 10 November 2026 as part of its November release, naming the GitHub Copilot plugin for JetBrains IDEs. Microsoft is the assigning authority and credits no outside researcher. GitHub's advisory database mirrored the record the same day, where it carries a moderate label and the same score.

## How it works

The weakness is classed as CWE-77, improper neutralization of special elements used in a command, and the stated effect is that an authorized attacker can disclose information locally. The published vector, AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N, means a caller who already has a low-privileged local account, needs no user interaction, and gains high impact on confidentiality only. Which command path accepts the unescaped input is not described.

## Who is affected

Plugin versions from 1.0.0 up to, but not including, 1.17.0-251 are listed as affected, across the JetBrains IDEs the plugin supports. Developer workstations carry the exposure, because the attack is local and the impact is reading data the plugin can reach.

## What to do

Update the GitHub Copilot plugin in every JetBrains IDE to 1.17.0-251 or later, the first version Microsoft lists as unaffected. Shared and multi-user developer hosts deserve the update first, since a low-privileged local account is all the flaw needs.

## Quick facts

- **Affected:** GitHub Copilot plugin for JetBrains IDEs, 1.0.0 up to 1.17.0-251
- **Fixed in:** 1.17.0-251
- **CVE:** CVE-2026-83953, published 10 November 2026, Microsoft as the assigning authority
- **CVSS:** 5.5 base (v3.1), AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
- **Attack type:** Command injection, CWE-77, leading to local information disclosure

## Sources

1. [Microsoft Advisory](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83953)
2. [GitHub Advisory](https://github.com/advisories/GHSA-5pr7-c8pm-c229)
3. [CVE Record](https://cveawg.mitre.org/api/cve/CVE-2026-83953)