CVE-2026-21523
HIGHDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
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
Exploit Intelligence
Moderate risk: more likely to be exploited than 53% of all known CVEs.
References
Related Vulnerabilities
Other CWE-367 (TOCTOU Race Condition) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-36980 | High | 8.1 | 83% | - | Fix |
| CVE-2024-30088 | High | 7.0 | 68% | KEV + Ransom | Fix |
| CVE-2004-0594 | Medium | 5.1 | 55% | - | Fix |
| CVE-2024-50379 | Critical | 9.8 | 44% | - | Fix |
| CVE-2023-38146 | High | 8.8 | 39% | - | Fix |
| CVE-2024-0132 | Critical | 9.0 | 38% | - | Fix |
Common questions
How do I fix CVE-2026-21523?
Upgrade Microsoft Visual Studio Code to 1.109.2 or later.
Is CVE-2026-21523 being actively exploited?
Not that we know of. CVE-2026-21523 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.79% is the estimated probability that it will be exploited in the next 30 days. That is higher than 53% of all scored CVEs.
How severe is CVE-2026-21523?
CVE-2026-21523 has a CVSS v3 base score of 8.0, rated important. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-21523 affect?
Published advisories record a fix for Microsoft Visual Studio Code (Windows application). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-21523
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-02-11.