CVE-2019-11251: K8s.io/kubernetes Kubernetes Kubectl Cp Vulnerable To Vulnerability

MODERATE
Advisory Identifier: GHSA-6qfg-8799-r575
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CVSS 5.7
CWE-59 CWE-61
Published
Advisory Summary

CVE-2019-11251 is a MODERATE (CVSS 5.7) kubernetes kubectl cp vulnerable to vulnerability (CWE-59: Improper Link Resolution Before File Access ('Link Following')) affecting K8s.io/kubernetes libraries in the Go ecosystem. The issue involves kubernetes kubectl cp vulnerable to symlink attack. Remediation is available by upgrading affected packages to version 1.13.11, 1.14.7, 1.16.0.

CVE-2019-11251 at a Glance

CVE Identifier CVE-2019-11251
GHSA Identifier GHSA-6qfg-8799-r575
Severity MODERATE
CVSS v3.1 Base Score 5.7
CWE Classification CWE-59: Improper Link Resolution Before File Access ('Link Following')
Affected Product K8s.io/kubernetes
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 5.7

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

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

How to Fix CVE-2019-11251

To remediate this vulnerability, upgrade all affected K8s.io/kubernetes dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

k8s.io/kubernetes fixed: 1.13.11 
Upgrade k8s.io/kubernetes to 1.13.11
k8s.io/kubernetes fixed: 1.14.7 
Upgrade k8s.io/kubernetes to 1.14.7
k8s.io/kubernetes fixed: 1.16.0 
Upgrade k8s.io/kubernetes to 1.16.0
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 k8s.io/kubernetes

How to Check if You Are Affected

To determine whether your application is affected by CVE-2019-11251, inspect your project dependencies for K8s.io/kubernetes:

inspect dependencies for k8s.io/kubernetes

Analyze the terminal output to locate any version of K8s.io/kubernetes in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.13.11), 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 K8s.io/kubernetes, 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

The Kubernetes kubectl cp command in versions 1.1-1.12, and versions prior to 1.13.11, 1.14.7, and 1.15.4 allows a combination of two symlinks provided by tar output of a malicious container to place a file outside of the destination directory specified in the kubectl cp invocation. This could be used to allow an attacker to place a nefarious file using a symlink, outside of the destination tree.

CVE-2019-11251 Affected K8s.io/kubernetes Versions

3 component(s)
Fixed Versions:
1.13.111.14.71.16.0
Product / Package Ecosystem Affected Versions Fixed Version
k8s.io/kubernetes
golang/k8s.io/kubernetes
Go
≥ 1.13.10
< 1.13.11
1.13.11
k8s.io/kubernetes
golang/k8s.io/kubernetes
Go
≥ 1.14.6
< 1.14.7
1.14.7
k8s.io/kubernetes
golang/k8s.io/kubernetes
Go
≥ 1.15.3
< 1.16.0
1.16.0

References

NVD — CVE-2019-11251 NVD
https://nvd.nist.gov/vuln/detail/CVE-2019-11251
K8s.io/kubernetes Source Repository REPOSITORY
https://github.com/kubernetes/kubernetes/issues/87773
K8s.io/kubernetes Source Repository REPOSITORY
https://github.com/kubernetes/kubernetes/pull/82143
groups.google.com/d/msg/kubernetes-an... WEB
https://groups.google.com/d/msg/kubernetes-announce/YYtEFdFimZ4/nZnOezZuBgAJ

Frequently Asked Questions

What is CVE-2019-11251?
CVE-2019-11251 is a security vulnerability in K8s.io/kubernetes involving Kubernetes kubectl cp Vulnerable to Symlink Attack under CWE-59: Improper Link Resolution Before File Access ('Link Following').
Which K8s.io/kubernetes versions are affected?
Affected versions include releases prior to 1.13.11, 1.14.7, 1.16.0 across affected packages: k8s.io/kubernetes.
What version fixes CVE-2019-11251?
Upgrading to 1.13.11, 1.14.7, 1.16.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is k8s.io/kubernetes affected?
Yes, k8s.io/kubernetes is affected in releases prior to 1.13.11, 1.14.7, 1.16.0. Upgrade your dependency to 1.13.11, 1.14.7, 1.16.0 or later.
What is the CVSS score of CVE-2019-11251?
CVE-2019-11251 has a CVSS v3.1 base score of 5.7 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N.
What CWE is associated with CVE-2019-11251?
CVE-2019-11251 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-2019-11251?
Run the dependency tree command: 'inspect dependencies for k8s.io/kubernetes'. 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-6qfg-8799-r575",
  "modified" : "2023-09-18T20:30:39Z",
  "published" : "2021-05-18T15:30:07Z",
  "aliases" : [ "CVE-2019-11251" ],
  "summary" : "Kubernetes kubectl cp Vulnerable to Symlink Attack",
  "details" : "The Kubernetes kubectl cp command in versions 1.1-1.12, and versions prior to 1.13.11, 1.14.7, and 1.15.4 allows a combination of two symlinks provided by tar output of a malicious container to place a file outside of the destination directory specified in the kubectl cp invocation. This could be used to allow an attacker to place a nefarious file using a symlink, outside of the destination tree.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "k8s.io/kubernetes"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.13.10"
      }, {
        "fixed" : "1.13.11"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "k8s.io/kubernetes"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.14.6"
      }, {
        "fixed" : "1.14.7"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "k8s.io/kubernetes"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.15.3"
      }, {
        "fixed" : "1.16.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2019-11251"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/kubernetes/kubernetes/issues/87773"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/kubernetes/kubernetes/pull/82143"
  }, {
    "type" : "WEB",
    "url" : "https://groups.google.com/d/msg/kubernetes-announce/YYtEFdFimZ4/nZnOezZuBgAJ"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-59", "CWE-61" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-05-17T21:58:06Z",
    "nvd_published_at" : null
  }
}