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CVE-2021-39135
August 31, 2021
"@npmcli/arborist", the library that calculates dependency trees and manages the node_modules folder hierarchy for the npm command line interface, aims to guarantee that package dependency contracts will be met, and the extraction of package contents will always be performed into the expected folder. This is accomplished by extracting package contents into a project's "node_modules" folder. If the "node_modules" folder of the root project or any of its dependencies is somehow replaced with a symbolic link, it could allow Arborist to write package dependencies to any arbitrary location on the file system. Note that symbolic links contained within package artifact contents are filtered out, so another means of creating a "node_modules" symbolic link would have to be employed. 1. A "preinstall" script could replace "node_modules" with a symlink. (This is prevented by using "--ignore-scripts".) 2. An attacker could supply the target with a git repository, instructing them to run "npm install --ignore-scripts" in the root. This may be successful, because "npm install --ignore-scripts" is typically not capable of making changes outside of the project directory, so it may be deemed safe. This is patched in @npmcli/arborist 2.8.2 which is included in npm v7.20.7 and above. For more information including workarounds please see the referenced GHSA-gmw6-94gg-2rc2.
Affected Packages
@npmcli/arborist (NPM):
Affected version(s) >=0.0.0 <2.8.2
Fix Suggestion:
Update to version 2.8.2
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CVSS v4
Base Score:
9.2
Attack Vector
LOCAL
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
HIGH
Subsequent System Integrity
HIGH
Subsequent System Availability
NONE
CVSS v3
Base Score:
8.2
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
CVSS v2
Base Score:
4.4
Access Vector
LOCAL
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
Weakness Type (CWE)
UNIX Symbolic Link (Symlink) Following
Improper Link Resolution Before File Access ('Link Following')
EPSS
Base Score:
0.21