CVE-2026-29783: github copilot-cli · OS Command Injection
Affects github copilot-cliSource CVE Database V5
Not known to be exploited · CVSS 7.5 High · fixed in 0.0.423 : patch github copilot-cli soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 35% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.0.423
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 6 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| githubcopilot-cli | Affected
| Fixed in– |
GitHubgithub/copilot-clipkg:github/github/copilot-cliOther threats | Affected
| Fixed in– |
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AI-suggested
- Immediate upgrade to GitHub Copilot CLI version 0.0.423 or later, where the vulnerability is patched.
- Implement strict validation and sanitization of any input that can influence commands executed by the CLI, including repository files (README, code comments, issue bodies), MCP server responses, and user instructions.
- Restrict or monitor the use of Copilot CLI in automated environments or CI/CD pipelines to prevent unintentional execution of injected commands.
- Educate developers and users about the risks of prompt injection and encourage cautious review of repository content and external inputs that may affect CLI behavior.
- Employ endpoint detection and response (EDR) tools to monitor for suspicious command execution patterns indicative of exploitation attempts.
- Consider isolating development environments or using containerization to limit the blast radius of potential compromises.
- Review and tighten permissions and approval workflows around write-capable operations initiated via the CLI to detect anomalous activities.
- Monitor GitHub advisories and security updates for any emerging exploit reports or additional patches.
Description
The shell tool within GitHub Copilot CLI versions prior to and including 0.0.422 can allow arbitrary code execution through crafted bash parameter expansion patterns. An attacker who can influence the commands executed by the agent (e.g., via prompt injection through repository files, MCP server responses, or user instructions) can exploit bash parameter transformation operators to execute hidden commands, bypassing the safety assessment that classifies commands as "read-only." This has been patched in version 0.0.423. The vulnerability stems from how the CLI's shell safety assessment evaluates commands before execution. The safety layer parses and classifies shell commands as either read-only (safe) or write-capable (requires user approval). However, several bash parameter expansion features can embed executable code within arguments to otherwise read-only commands, causing them to appear safe while actually performing arbitrary operations. The specific dangerous patterns are ${var@P}, ${var=value} / ${var:=value}, ${!var}, and nested $(cmd) or <(cmd) inside ${...} expansions. An attacker who can influence command text sent to the shell tool - for example, through prompt injection via malicious repository content (README files, code comments, issue bodies), compromised or malicious MCP server responses, or crafted user instructions containing obfuscated commands - could achieve arbitrary code execution on the user's workstation. This is possible even in permission modes that require user approval for write operations, since the commands can appear to use only read-only utilities to ultimately trigger write operations. Successful exploitation could lead to data exfiltration, file modification, or further system compromise.