CVE-2021-39134

Publication date 31 August 2021

Last updated 24 July 2024


Ubuntu priority

Cvss 3 Severity Score

7.8 · High

Score breakdown

`@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, in part, accomplished by resolving dependency specifiers defined in `package.json` manifests for dependencies with a specific name, and nesting folders to resolve conflicting dependencies. When multiple dependencies differ only in the case of their name, Arborist’s internal data structure saw them as separate items that could coexist within the same level in the `node_modules` hierarchy. However, on case-insensitive file systems (such as macOS and Windows), this is not the case. Combined with a symlink dependency such as `file:/some/path`, this allowed an attacker to create a situation in which arbitrary contents could be written to any location on the filesystem. For example, a package `pwn-a` could define a dependency in their `package.json` file such as `“foo”: “file:/some/path”`. Another package, `pwn-b` could define a dependency such as `FOO: “file:foo.tgz”`. On case-insensitive file systems, if `pwn-a` was installed, and then `pwn-b` was installed afterwards, the contents of `foo.tgz` would be written to `/some/path`, and any existing contents of `/some/path` would be removed. Anyone using npm v7.20.6 or earlier on a case-insensitive filesystem is potentially affected. This is patched in @npmcli/arborist 2.8.2 which is included in npm v7.20.7 and above.

Status

Package Ubuntu Release Status
npm 24.10 oracular
Not affected
24.04 LTS noble
Not affected
23.10 mantic Ignored end of life, was needs-triage
23.04 lunar Ignored end of life, was needs-triage
22.10 kinetic Ignored end of life, was needs-triage
22.04 LTS jammy
Not affected
21.10 impish Ignored end of life
21.04 hirsute Ignored end of life
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
14.04 LTS trusty Ignored end of ESM support, was needs-triage

Severity score breakdown

Parameter Value
Base score 7.8 · High
Attack vector Local
Attack complexity Low
Privileges required None
User interaction Required
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H