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Vulnerability details: VCID-9vk1-2ysq-3ygd
Vulnerability ID VCID-9vk1-2ysq-3ygd
Aliases CVE-2021-39135
GHSA-gmw6-94gg-2rc2
Summary UNIX Symbolic Link (Symlink) Following `@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. A `preinstall` script could replace `node_modules` with a symlink. (This is prevented by using `--ignore-scripts`.) 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 which is included in npm v7.20.7. For more information including workarounds please see the referenced GHSA-gmw6-94gg-2rc2.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (5)
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-61 UNIX Symbolic Link (Symlink) Following
CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-59 Improper Link Resolution Before File Access ('Link Following')
System Score Found at
cvssv3 8.1 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-39135.json
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
epss 0.00211 https://api.first.org/data/v1/epss?cve=CVE-2021-39135
cvssv3.1 8.2 https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
generic_textual HIGH https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
cvssv3.1 8.1 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv3.1_qr HIGH https://github.com/advisories/GHSA-gmw6-94gg-2rc2
cvssv3.1 8.2 https://github.com/npm/arborist
generic_textual HIGH https://github.com/npm/arborist
cvssv3.1 8.2 https://github.com/npm/arborist/security/advisories/GHSA-gmw6-94gg-2rc2
cvssv3.1_qr HIGH https://github.com/npm/arborist/security/advisories/GHSA-gmw6-94gg-2rc2
generic_textual HIGH https://github.com/npm/arborist/security/advisories/GHSA-gmw6-94gg-2rc2
cvssv3.1 8.2 https://nvd.nist.gov/vuln/detail/CVE-2021-39135
generic_textual HIGH https://nvd.nist.gov/vuln/detail/CVE-2021-39135
cvssv3.1 8.2 https://www.npmjs.com/package/@npmcli/arborist
generic_textual HIGH https://www.npmjs.com/package/@npmcli/arborist
cvssv3.1 8.2 https://www.oracle.com/security-alerts/cpuoct2021.html
generic_textual HIGH https://www.oracle.com/security-alerts/cpuoct2021.html
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-39135.json
https://api.first.org/data/v1/epss?cve=CVE-2021-39135
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-39135
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://github.com/npm/arborist
https://www.npmjs.com/package/@npmcli/arborist
https://www.oracle.com/security-alerts/cpuoct2021.html
1999745 https://bugzilla.redhat.com/show_bug.cgi?id=1999745
993405 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=993405
CVE-2021-39135 https://nvd.nist.gov/vuln/detail/CVE-2021-39135
GHSA-gmw6-94gg-2rc2 https://github.com/advisories/GHSA-gmw6-94gg-2rc2
GHSA-gmw6-94gg-2rc2 https://github.com/npm/arborist/security/advisories/GHSA-gmw6-94gg-2rc2
GLSA-202405-29 https://security.gentoo.org/glsa/202405-29
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-39135.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N Found at https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N Found at https://github.com/npm/arborist
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N Found at https://github.com/npm/arborist/security/advisories/GHSA-gmw6-94gg-2rc2
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-39135
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N Found at https://www.npmjs.com/package/@npmcli/arborist
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N Found at https://www.oracle.com/security-alerts/cpuoct2021.html
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.43507
EPSS Score 0.00211
Published At April 1, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-04-01T12:48:48.920958+00:00 GitLab Importer Import https://gitlab.com/gitlab-org/advisories-community/-/blob/main/npm/@npmcli/arborist2/CVE-2021-39135.yml 38.0.0