CVE-2019-18658: Helm.sh/helm Helm Unsafe Link Following Vulnerability

CRITICAL
Advisory Identifier: GHSA-p5pc-m4q7-7qm9
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CVSS 9.8
CWE-59
Published
Advisory Summary

CVE-2019-18658 is a CRITICAL (CVSS 9.8) helm unsafe link following vulnerability (CWE-59: Improper Link Resolution Before File Access ('Link Following')) affecting Helm.sh/helm libraries in the Go ecosystem. The issue involves helm unsafe link following. Remediation is available by upgrading affected packages to version 2.15.2.

CVE-2019-18658 at a Glance

CVE Identifier CVE-2019-18658
GHSA Identifier GHSA-p5pc-m4q7-7qm9
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-59: Improper Link Resolution Before File Access ('Link Following')
Affected Product Helm.sh/helm
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 9.8

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

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

How to Fix CVE-2019-18658

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

helm.sh/helm fixed: 2.15.2 
Upgrade helm.sh/helm to 2.15.2
Verify Direct and Transitive Dependencies

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

inspect dependencies for helm.sh/helm

How to Check if You Are Affected

To determine whether your application is affected by CVE-2019-18658, inspect your project dependencies for Helm.sh/helm:

inspect dependencies for helm.sh/helm

Analyze the terminal output to locate any version of Helm.sh/helm in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.15.2), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-59: Improper Link Resolution Before File Access ('Link Following'), where the product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource. In Helm.sh/helm, 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 Helm 2.x before 2.15.2, commands that deal with loading a chart as a directory or packaging a chart provide an opportunity for a maliciously designed chart to include sensitive content such as `/etc/passwd`, or to execute a denial of service (DoS) via a special file such as /dev/urandom, via symlinks. No version of Tiller is known to be impacted. This is a client-only issue.

CVE-2019-18658 Affected Helm.sh/helm Versions

1 component(s)
Fixed Versions:
2.15.2
Product / Package Ecosystem Affected Versions Fixed Version
helm.sh/helm
golang/helm.sh/helm
Go
≥ 2.0.0
< 2.15.2
2.15.2

References

NVD — CVE-2019-18658 NVD
https://nvd.nist.gov/vuln/detail/CVE-2019-18658
Helm.sh/helm Source Repository REPOSITORY
https://github.com/helm/helm
Helm.sh/helm Security Information SECURITY
https://helm.sh/blog/2019-10-30-helm-symlink-security-notice

Frequently Asked Questions

What is CVE-2019-18658?
CVE-2019-18658 is a security vulnerability in Helm.sh/helm involving Helm Unsafe Link Following under CWE-59: Improper Link Resolution Before File Access ('Link Following').
Which Helm.sh/helm versions are affected?
Affected versions include releases prior to 2.15.2 across affected packages: helm.sh/helm.
What version fixes CVE-2019-18658?
Upgrading to 2.15.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is helm.sh/helm affected?
Yes, helm.sh/helm is affected in releases prior to 2.15.2. Upgrade your dependency to 2.15.2 or later.
What is the CVSS score of CVE-2019-18658?
CVE-2019-18658 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2019-18658?
CVE-2019-18658 is classified under CWE-59: Improper Link Resolution Before File Access ('Link Following') (The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.).
How can I check Go dependencies for CVE-2019-18658?
Run the dependency tree command: 'inspect dependencies for helm.sh/helm'. 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-p5pc-m4q7-7qm9",
  "modified" : "2023-09-26T19:48:05Z",
  "published" : "2022-05-24T22:01:14Z",
  "aliases" : [ "CVE-2019-18658" ],
  "summary" : "Helm Unsafe Link Following",
  "details" : "In Helm 2.x before 2.15.2, commands that deal with loading a chart as a directory or packaging a chart provide an opportunity for a maliciously designed chart to include sensitive content such as `/etc/passwd`, or to execute a denial of service (DoS) via a special file such as /dev/urandom, via symlinks. No version of Tiller is known to be impacted. This is a client-only issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "helm.sh/helm"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.0"
      }, {
        "fixed" : "2.15.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2019-18658"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/helm/helm"
  }, {
    "type" : "WEB",
    "url" : "https://helm.sh/blog/2019-10-30-helm-symlink-security-notice"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-59" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-07-17T23:57:06Z",
    "nvd_published_at" : "2019-11-12T14:15:00Z"
  }
}