CVE-2021-39134: UNIX Symbolic Link (Symlink) Following in @npmcli/arborist
First published: Tue Aug 31 2021(Updated: )
`@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.
Credit: security-advisories@github.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| npmjs arborist node.js | <2.8.2 | |
| npm | <7.20.7 | |
| Oracle GraalVM Enterprise Edition | =20.3.3 | |
| Oracle GraalVM Enterprise Edition | =21.2.0 | |
| siemens sinec infrastructure network services | <1.0.1.1 |
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Reference Links
Frequently Asked Questions
What is the vulnerability ID for this vulnerability?
The vulnerability ID for this vulnerability is CVE-2021-39134.
What is the severity of CVE-2021-39134?
The severity of CVE-2021-39134 is high (7.8).
What software is affected by CVE-2021-39134?
The software affected by CVE-2021-39134 includes Npmjs Arborist (up to version 2.8.2), Oracle GraalVM (version 20.3.3 and 21.2.0), and Siemens Sinec Infrastructure Network Services (up to version 1.0.1.1).
What is the description of CVE-2021-39134?
CVE-2021-39134 is a vulnerability in `@npmcli/arborist`, a library used by npm to manage package dependency trees and the `node_modules` folder hierarchy.
How can I fix CVE-2021-39134?
To fix CVE-2021-39134, you should update Npmjs Arborist to a version higher than 2.8.2 and Siemens Sinec Infrastructure Network Services to a version higher than 1.0.1.1.
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- source/MITRE
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- agent/softwarecombine
- collector/nvd-index
- agent/software-canonical-lookup-request
- vendor/npmjs
- canonical/npmjs arborist node.js
- canonical/npm
- vendor/oracle
- canonical/oracle graalvm enterprise edition
- version/oracle graalvm enterprise edition/20.3.3
- version/oracle graalvm enterprise edition/21.2.0
- vendor/siemens
- canonical/siemens sinec infrastructure network services