CVE-2021-4435 | Yarn: untrusted search path

An untrusted search path vulnerability was found in Yarn. When a victim runs certain Yarn commands in a directory with attacker-controlled content, malicious commands could be executed in unexpected ways.

Published: 2024-02-04 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-4435 is rated Low Risk (36.4/100): CVSS High severity, with low exploitation likelihood (EPSS 0.05%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-4435

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-01-05 0.04% 0.05% +0.01%
2 2025-11-21 0.11% 0.04% -0.07%
3 2025-11-18 — 0.11% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-4435

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.7 3.1 HIGH
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.0 6.0 [email protected]
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]

Weakness enumeration for CVE-2021-4435

GitHub Security Advisory for CVE-2021-4435

GHSA-mpwj-fcr6-x34c · Severity: high · Ecosystem: npm — Yarn untrusted search path vulnerability

OS Trackers for CVE-2021-4435

vendor priority summary link
debian not yet assigned CVE-2021-4435 not yet assigned priority: Debian including 1 source packages (node-yarnpkg), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2021-4435
redhat medium — https://access.redhat.com/security/cve/CVE-2021-4435
ubuntu medium CVE-2021-4435 medium priority: Ubuntu including 1 source packages (node-yarnpkg), 11 status rows across 11 suites (bionic, focal, jammy, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 3, needs-triage 3, ignored 2, needed 2, not-affected 1. https://ubuntu.com/security/CVE-2021-4435

Affected software / configurations for CVE-2021-4435

Vendor Product Version Raw CPE
yarnpkg yarn < 1.22.13 cpe:2.3:a:yarnpkg:yarn:*:*:*:*:*:*:*:*

References for CVE-2021-4435

cvelogic Threat Intelligence