CVE-2020-21514: Fluentd ui Fluent Fluentd And Fluent-ui Use Vulnerability

HIGH
Advisory Identifier: GHSA-wrxf-x8rm-6ggg
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CVSS 8.8
CWE-276
Published
Advisory Summary

CVE-2020-21514 is a HIGH (CVSS 8.8) fluent fluentd and fluent-ui use vulnerability (CWE-276: Incorrect Default Permissions) affecting Fluentd ui libraries in the RubyGems ecosystem. The issue involves fluent fluentd and fluent-ui use default password. Remediation is available in the latest vendor maintenance releases.

CVE-2020-21514 at a Glance

CVE Identifier CVE-2020-21514
GHSA Identifier GHSA-wrxf-x8rm-6ggg
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-276: Incorrect Default Permissions
Affected Product Fluentd ui
Package Ecosystem RubyGems
Published Date
Last Updated

Security Impact

CVSS: 8.8

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:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
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-2020-21514

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

fluentd-ui fixed: Latest secure release 
Upgrade fluentd-ui to Latest secure release
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 fluentd-ui

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-21514, inspect your project dependencies for Fluentd ui:

inspect dependencies for fluentd-ui

Analyze the terminal output to locate any version of Fluentd ui in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), 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-276: Incorrect Default Permissions, where during installation, installed file permissions are set to allow anyone to modify those files. In Fluentd ui, 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

An issue was discovered in Fluent-ui v.1.2.2 allows attackers to gain escalated privileges and execute arbitrary code due to a default password.

CVE-2020-21514 Affected Fluentd ui Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
fluentd-ui
gem/fluentd-ui
RubyGems
≤ 1.2.2

References

NVD — CVE-2020-21514 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-21514
Fluentd ui Source Repository REPOSITORY
https://github.com/fluent/fluentd-ui/issues/295
Fluentd ui Source Repository REPOSITORY
https://github.com/fluent/fluentd/issues/2722
Fluentd ui Source Repository REPOSITORY
https://github.com/fluent/fluentd-ui
Fluentd ui Source Repository REPOSITORY
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/fluentd-ui/CVE-2020-21514.yml

Frequently Asked Questions

What is CVE-2020-21514?
CVE-2020-21514 is a security vulnerability in Fluentd ui involving Fluent Fluentd and Fluent-ui use default password under CWE-276: Incorrect Default Permissions.
Which Fluentd ui versions are affected?
Affected versions include releases prior to current release patches across affected packages: fluentd-ui.
What version fixes CVE-2020-21514?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is fluentd-ui affected?
Yes, fluentd-ui is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2020-21514?
CVE-2020-21514 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2020-21514?
CVE-2020-21514 is classified under CWE-276: Incorrect Default Permissions (During installation, installed file permissions are set to allow anyone to modify those files.).
How can I check RubyGems dependencies for CVE-2020-21514?
Run the dependency tree command: 'inspect dependencies for fluentd-ui'. 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-wrxf-x8rm-6ggg",
  "modified" : "2025-06-23T14:22:27Z",
  "published" : "2023-04-04T15:30:27Z",
  "aliases" : [ "CVE-2020-21514" ],
  "summary" : "Fluent Fluentd and Fluent-ui use default password",
  "details" : "An issue was discovered in Fluent-ui v.1.2.2 allows attackers to gain escalated privileges and execute arbitrary code due to a default password.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "fluentd-ui"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.2.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-21514"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fluent/fluentd-ui/issues/295"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fluent/fluentd/issues/2722"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/fluent/fluentd-ui"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/fluentd-ui/CVE-2020-21514.yml"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-276" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-08-11T18:59:49Z",
    "nvd_published_at" : "2023-04-04T15:15:00Z"
  }
}