Threat Intelligence / CVE / CVE-2026-21523

CVE-2026-21523

CVSS 8 (HIGH) · EPSS 0.0% · Priority 4.4/10 · Published 2026-02-10

As of 2026-05-11, CVE-2026-21523 is a CVSS 8 (HIGH-severity) vulnerability. EPSS exploitation probability 0.0%. Threadlinqs Intelligence tracks 1 threat exploiting it.

Last updated: 2026-05-11

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.

CVSS v3 vector: 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

Weaknesses (CWE)

CWE-367

Threats tracking this CVE

CVE-2026-21523: TOCTOU Race Condition in GitHub Copilot / Visual Studio Enables Authorized Network Code Execution — HIGH

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21523

Full detection coverage & IOCs for threats exploiting CVE-2026-21523 are available via the Threadlinqs MCP server (Purple tier). View plans →

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Enriched from CVE.org, NVD (this product uses the NVD API but is not endorsed or certified by the NVD), FIRST EPSS, CISA KEV, and GitHub Security Advisories.