Security readout for executives and security teams
Plain-English summary
This issue affects Yarn command execution when a user runs certain Yarn commands inside a directory containing attacker-controlled content. In that situation, Yarn may search an unsafe path and execute malicious commands unexpectedly. It requires user action and local context, but successful exploitation could affect confidentiality, integrity, and availability.
Executive priority
Treat this as a targeted developer and build-chain risk, not a broad internet-facing emergency. Prioritize environments that process untrusted source code, especially CI and developer onboarding workflows, because compromise there can lead to credential theft or downstream software tampering.
Technical view
CVE-2021-4435 is a CWE-426 untrusted search path issue in Yarn. The bundle identifies Yarn 1.22.13 as affected. CVSS 3.1 is 7.7 with local attack vector, high complexity, no privileges, required user interaction, changed scope, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely on developer workstations or build environments where Yarn 1.22.13 is run inside repositories, archives, or directories containing attacker-controlled files. Fedora and EPEL yarnpkg entries are listed with defaultStatus unaffected in the provided data.
Exploitation context
The source bundle does not show CISA KEV listing or other evidence of active exploitation. Exploitation depends on convincing a victim to run certain Yarn commands from a directory containing attacker-controlled content. No remote, unauthenticated exploitation path is described.
Researcher notes
The bundle names Yarn 1.22.13 and references a Yarn commit and release, but it does not provide detailed fixed-version guidance. Avoid assuming exploit maturity or package remediation beyond the cited records. Focus validation on unsafe search path behavior and execution context.
Mitigation direction
- Inventory developer and build systems for Yarn 1.22.13.
- Avoid running Yarn commands in untrusted directories until vendor guidance is confirmed.
- Check Yarn upstream and distribution advisories for fixed package guidance.
- Use clean, trusted build workspaces for repositories from untrusted sources.
- For Fedora or EPEL yarnpkg, confirm status through Red Hat or Fedora channels.
Validation and detection
- Check installed Yarn versions on developer machines and CI images.
- Review CI jobs that run Yarn against external pull requests or uploaded source trees.
- Confirm whether Yarn runs inside attacker-controlled or partially trusted directories.
- Validate package status against the cited CVE and vendor advisory pages.
- Record compensating controls if an immediate update is unavailable.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-426: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-4435 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H16Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.7HighVector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://access.redhat.com/security/cve/CVE-2021-4435CVE reference · vdb-entry, x_refsource_REDHAT
- RHBZ#2262284CVE reference · issue-tracking, x_refsource_REDHAT
- https://github.com/yarnpkg/yarn/commit/67fcce88935e45092ffa2674c08053f1ef5268a1CVE reference
- https://github.com/yarnpkg/yarn/releases/tag/v1.22.13CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Untrusted Search Path
Untrusted Search Path represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.