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yeoman-environment Vulnerable to Arbitrary Package Installation without User Confirmation

High severity GitHub Reviewed Published May 22, 2026 in yeoman/environment • Updated Jul 8, 2026

Package

npm yeoman-environment (npm)

Affected versions

>= 2.9.0, < 6.0.1

Patched versions

6.0.1

Description

Impact

yeoman-environment versions >= 2.9.0 and < 6.0.1 install missing local generator packages from caller-supplied package names without user confirmation. In downstream consumers that pass attacker-controlled project configuration into this path, this can result in arbitrary package installation and code execution during CLI bootstrap.

The vulnerable method is installLocalGenerators(), which calls repository.install() directly without prompting the user.

Patches

Upgrade to yeoman-environment 6.0.1, which adds an interactive confirmation prompt before installation (PR #753).

Workarounds

None.

Resources

References

@mshima mshima published to yeoman/environment May 22, 2026
Published to the GitHub Advisory Database May 26, 2026
Reviewed May 26, 2026
Published by the National Vulnerability Database Jun 16, 2026
Last updated Jul 8, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(4th percentile)

Weaknesses

Inclusion of Functionality from Untrusted Control Sphere

The product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere. Learn more on MITRE.

CVE ID

CVE-2026-42089

GHSA ID

GHSA-vv9j-gjw2-j8wp

Source code

Credits

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