CVE-2026-29783Public exploitNetwork attack vector

Arbitrary code execution via misclassified shell expansions

Published Mar 6, 2026 · Updated Mar 6, 2026

OS command injection in GitHub Copilot CLI 0.0.422 and earlier allows attackers to execute arbitrary code through crafted shell-tool input. The shell safety assessor marks commands using read-only utilities as safe without rejecting executable Bash parameter expansions such as @P, assignment, indirection, or nested substitution. Exploitation requires attacker-influenced agent command text from repository content, MCP responses, or instructions and runs with the user's workstation privileges.

CVSS severity7.5
High
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in GitHub Copilot CLI 0.0.422 and earlier allows attackers to execute arbitrary code through crafted shell-tool input. The shell safety assessor marks commands using read-only utilities as safe without rejecting executable Bash parameter expansions such as @P, assignment, indirection, or nested substitution. Exploitation requires attacker-influenced agent command text from repository content, MCP responses, or instructions and runs with the user's workstation privileges.

The record

CVE
CVE-2026-29783
Published
Mar 6, 2026
Updated
Mar 6, 2026
Vendor
Twitter
Product
GitHub Copilot CLI
Classifications
CWE-78, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 0.0.422

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Twitter · GitHub Copilot CLIversion=<= 0.0.422

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.5GitHubCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Unix Shell

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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