CVE-2026-45033
GitHub Copilot CLI: Nested Bare Repository Can Execute Arbitrary Commands via core.fsmonitor
- Published
- May 13, 2026
- Updated
- May 13, 2026
- Assigning CNA
- GitHub_M
- Evidence observed
- Aug 4, 2026
Primary CVSS
nvd · CVSS 4.0
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XLow · next 30 days
- Percentile
- 28.6%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
GitHub Copilot CLI brings AI-powered coding assistance directly to your command line. Prior to 1.0.43, a security vulnerability has been identified in GitHub Copilot CLI where a malicious bare git repository nested inside a project directory can achieve arbitrary code execution when the agent performs git operations. By exploiting git's automatic bare repository discovery during directory traversal, an attacker can set core.fsmonitor or other executable config keys to run arbitrary commands without user awareness or approval. The vulnerability arises because git's core.fsmonitor config key (and 15+ similar keys such as core.hookspath, diff.external, merge.tool, etc.) can specify arbitrary shell commands that git will execute as part of normal operations like status, diff, or rev-parse. This vulnerability is fixed in 1.0.43.
Sources
1CVE-2026-45033 PoC for Claude Code, not Github Copilot. Worked for Haiku 4.5.
Responsible use
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