CVE-2026-21523: microsoft microsoft visual studio code copilot chat extension
CVSS: 8.0v3.1HighAnalyzed
Published 10-02-2026Last modified 19-08-2026
Vulnerability summary
CVE-2026-21523 is a high (CVSS 8.0) vulnerability in microsoft microsoft visual studio code copilot chat extension. EPSS estimates a 0.78% chance of exploitation in the next 30 days, higher than 54.9% of scored vulnerabilities.
CVSS score
8.0/10
010
High · v3.1 (CVE.org)EPSS score
0.78%
0%100%
Low · -0.03 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 10-02-2026PublishedVulnerability first disclosed.
- 19-08-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
2 scores · 2 sources · 1 versionHigh 8.0Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:CSourcesAll 2 agree
- NVDNIST8.0HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.78%
Chance of exploitation in the next 30 days
Percentile
55%
Versus all other CVEs
30-day change
-0.03 pp
From 0.81% on 19-09-2026
19-09-202619-10-2026
EPSS score0.78%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Microsoft2 products
- microsoft visual studio code copilot chat extension≥ 0.27.0, < 0.37.1
- visual studio code≥ 1.0.0, < 1.110.1 | < 1.109.2
1 vendor · 2 products
