Home/CVE/Time-of-check time-of-use (toctou) race condition in GitHub Copilot and Visual Studio allows an authorized attacker to e
CVE

CVE-2026-21523

Time-of-check time-of-use (toctou) race condition in GitHub Copilot and Visual Studio allows an authorized attacker to e

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.

HIGH · CVSS 8 EPSS 0.00035
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules7 YARA rules0
⬡

Weakness Classification

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

Affected Products & Versions

1
microsoft visual studio code< 1.109.2
◈

Sigma Hunt Rules

7
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
producthighRenamed Visual Studio Code Tunnel Execution
productmediumNetwork Connection Initiated To Visual Studio Code Tunnels Domain
productmediumVisual Studio Code Tunnel Remote File Creation
productmediumDNS Query To Visual Studio Code Tunnels Domain
productmediumVisual Studio Code Tunnel Execution
productmediumVisual Studio Code Tunnel Shell Execution
▣

Scoring & Timeline

8
HIGH · CVSS v3.1 · secure@microsoft.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD10 Feb 2026 · 06:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

1
msrcCVE-2026-21523Remote Code Execution
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