CVE-2019-10773: Yarn Yarn Improper Link Resolution Before Vulnerability

HIGH
Advisory Identifier: GHSA-5xf4-f2fq-f69j
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CVSS 7.8
CWE-78
Published
Advisory Summary

CVE-2019-10773 is a HIGH (CVSS 7.8) yarn improper link resolution before vulnerability (CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')) affecting Yarn libraries in the npm ecosystem. The issue involves yarn improper link resolution before file access (link following). Remediation is available by upgrading affected packages to version 1.22.0.

CVE-2019-10773 at a Glance

CVE Identifier CVE-2019-10773
GHSA Identifier GHSA-5xf4-f2fq-f69j
Severity HIGH
CVSS v3.1 Base Score 7.8
CWE Classification CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Affected Product Yarn
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2019-10773

To remediate this vulnerability, upgrade all affected Yarn dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

yarn fixed: 1.22.0 
npm install yarn@1.22.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls yarn

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2019-10773, inspect your project dependencies using npm:

npm ls yarn

Analyze the terminal output to locate any version of Yarn in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.22.0), your application is affected.

Note: The npm ls yarn command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'), where the product constructs all or part of an os command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended os command when it is sent to a downstream component. In Yarn, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

In Yarn before 1.21.1, the package install functionality can be abused to generate arbitrary symlinks on the host filesystem by using specially crafted "bin" keys. Existing files could be overwritten depending on the current user permission set.

CVE-2019-10773 Affected Yarn Versions

1 component(s)
Fixed Versions:
1.22.0
Product / Package Ecosystem Affected Versions Fixed Version
yarn
npm/yarn
npm
< 1.22.0
1.22.0

References

NVD — CVE-2019-10773 NVD
https://nvd.nist.gov/vuln/detail/CVE-2019-10773
Yarn Source Repository REPOSITORY
https://github.com/yarnpkg/yarn/issues/7761#issuecomment-565493023
Yarn Source Repository REPOSITORY
https://github.com/yarnpkg/yarn/pull/7755
Security Fix Commit FIX COMMIT
https://github.com/yarnpkg/yarn/commit/039bafd74b7b1a88a53a54f8fa6fa872615e90e7
access.redhat.com/errata/rhsa-2020:04... WEB
https://access.redhat.com/errata/RHSA-2020:0475
blog.daniel-ruf.de/critical-design-fla... WEB
https://blog.daniel-ruf.de/critical-design-flaw-npm-pnpm-yarn
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3HIZW4NZVV5QY5WWGW2JRP3FHYKZ6ZJ5
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ITY5BC63CCC647DFNUQRQ5AJDKUKUNBI
snyk.io/vuln/snyk-js-yarn-5... WEB
https://snyk.io/vuln/SNYK-JS-YARN-537806,

Frequently Asked Questions

What is CVE-2019-10773?
CVE-2019-10773 is a security vulnerability in Yarn involving Yarn Improper link resolution before file access (Link Following) under CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection').
Which Yarn versions are affected?
Affected versions include releases prior to 1.22.0 across affected packages: yarn.
What version fixes CVE-2019-10773?
Upgrading to 1.22.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is yarn affected?
Yes, yarn is affected in releases prior to 1.22.0. Upgrade your dependency to 1.22.0 or later.
What is the CVSS score of CVE-2019-10773?
CVE-2019-10773 has a CVSS v3.1 base score of 7.8 (HIGH) with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2019-10773?
CVE-2019-10773 is classified under CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') (The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.).
How can I check npm dependencies for CVE-2019-10773?
Run the dependency tree command: 'npm ls yarn'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5xf4-f2fq-f69j",
  "modified" : "2023-09-08T22:40:47Z",
  "published" : "2020-02-14T23:10:16Z",
  "aliases" : [ "CVE-2019-10773" ],
  "summary" : "Yarn Improper link resolution before file access (Link Following)",
  "details" : "In Yarn before 1.21.1, the package install functionality can be abused to generate arbitrary symlinks on the host filesystem by using specially crafted \"bin\" keys. Existing files could be overwritten depending on the current user permission set.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "yarn"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.22.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.21.1"
    }
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2019-10773"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/yarnpkg/yarn/issues/7761#issuecomment-565493023"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/yarnpkg/yarn/pull/7755"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/yarnpkg/yarn/commit/039bafd74b7b1a88a53a54f8fa6fa872615e90e7"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0475"
  }, {
    "type" : "WEB",
    "url" : "https://blog.daniel-ruf.de/critical-design-flaw-npm-pnpm-yarn"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3HIZW4NZVV5QY5WWGW2JRP3FHYKZ6ZJ5"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ITY5BC63CCC647DFNUQRQ5AJDKUKUNBI"
  }, {
    "type" : "WEB",
    "url" : "https://snyk.io/vuln/SNYK-JS-YARN-537806,"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-78" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-02-13T21:01:35Z",
    "nvd_published_at" : null
  }
}