CVE-2021-4435

Code execution via working-directory executable resolution

Published Feb 4, 2024 · Updated Jun 17, 2025

Untrusted search path handling in Yarn before 1.22.13 allows attackers to execute commands when a user runs Yarn in a crafted directory. In src/util/child.js, Yarn passed bare program names to Node.js child-process launch functions without rejecting executables found in the working directory. Exploitation requires a victim to invoke an affected Yarn command from attacker-controlled content, after which the planted executable runs with that user's privileges.

CVSS severity7.7
High
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Untrusted search path handling in Yarn before 1.22.13 allows attackers to execute commands when a user runs Yarn in a crafted directory. In src/util/child.js, Yarn passed bare program names to Node.js child-process launch functions without rejecting executables found in the working directory. Exploitation requires a victim to invoke an affected Yarn command from attacker-controlled content, after which the planted executable runs with that user's privileges.

The record

CVE
CVE-2021-4435
Published
Feb 4, 2024
Updated
Jun 17, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-426, T1574.008
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.7Fedora ProjectCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-426Untrusted Search Path
T1574.008Path Interception by Search Order Hijacking

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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