Vulnerabilities in pkg:golang/github.com/concourse/dex

PACKAGE
Advisory Identifier: GHSA-627p-rr78-99rj
Advisory Summary

CVE-2020-5415 is a HIGH (CVSS 7.5) gitlab auth uses full name vulnerability (CWE-290: Authentication Bypass by Spoofing) affecting Github.com/concourse/concourse libraries in the Go ecosystem. The issue involves gitlab auth uses full name instead of username as user id, allowing impersonation. Remediation is available by upgrading affected packages to version 6.4.1, 6.3.1, 0.0.0-20200730150203-821b48abfd88, 0.0.0-20200730151558-b00d1c8d8576, 1.6.1-0.20200730151558-b00d1c8d8576.

1 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:golang/github.com/concourse/dex

1 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:golang/github.com/concourse/dex. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-627p-rr78-99rj CVE-2020-5415 HIGH GitLab auth uses full name instead of username as user ID, allowing impersonation

CVE-2020-5415 at a Glance

CVE Identifier CVE-2020-5415
GHSA Identifier GHSA-627p-rr78-99rj
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-290: Authentication Bypass by Spoofing
Affected Product Github.com/concourse/concourse
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 7.5

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:N/A:N).

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 None (I:N)
Availability None (A:N)

How to Fix CVE-2020-5415

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

github.com/concourse/concourse fixed: 6.4.1
Upgrade github.com/concourse/concourse to 6.4.1
github.com/concourse/concourse fixed: 6.3.1
Upgrade github.com/concourse/concourse to 6.3.1
github.com/concourse/dex fixed: 6.4.1
Upgrade github.com/concourse/dex to 6.4.1
github.com/concourse/dex fixed: 6.3.1
Upgrade github.com/concourse/dex to 6.3.1
github.com/concourse/dex fixed: 0.0.0-20200730150203-821b48abfd88
Upgrade github.com/concourse/dex to 0.0.0-20200730150203-821b48abfd88
github.com/concourse/concourse fixed: 0.0.0-20200730151558-b00d1c8d8576
Upgrade github.com/concourse/concourse to 0.0.0-20200730151558-b00d1c8d8576
github.com/concourse/concourse fixed: 1.6.1-0.20200730151558-b00d1c8d8576
Upgrade github.com/concourse/concourse to 1.6.1-0.20200730151558-b00d1c8d8576
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 github.com/concourse/concourse

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-5415, inspect your project dependencies for Github.com/concourse/concourse:

inspect dependencies for github.com/concourse/concourse

Analyze the terminal output to locate any version of Github.com/concourse/concourse in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 6.4.1), 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-290: Authentication Bypass by Spoofing, where this attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. In Github.com/concourse/concourse, 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

### Impact Installations which use the GitLab auth connector are vulnerable to identity spoofing by way of configuring a GitLab account with the same full name as another GitLab user who is granted access to a Concourse team by having their full name listed under `users` in the team configuration or given to the `--gitlab-user` flag. See the [GitLab auth docs](https://concourse-ci.org/gitlab-auth.html) for details. Concourse installations which do not configure the GitLab auth connector are not affected. ### Patches Concourse [v6.3.1](https://github.com/concourse/concourse/releases/tag/v6.3.1) and [v6.4.1](https://github.com/concourse/concourse/releases/tag/v6.4.1) were both released with a fix on August 4th, 2020. Both versions change the GitLab connector to use the username, rather than the full name. This was always the intent, and the previous behavior was originally reported as a bug (concourse/dex#7) prior to being reported as a security issue. Any Concourse teams which configure GitLab users will have to switch each user from their full name to their username upon upgrading to these versions. ### Workarounds GitLab groups do not have this vulnerability, so GitLab users may be moved into groups which are then configured in the Concourse team. ### References * concourse/dex#12: PR with the fix ### For more information If you have any questions or comments about this advisory, you may reach us privately at [concourseteam+security@gmail.com](mailto:concourseteam+security@gmail.com).

CVE-2020-5415 Affected Github.com/concourse/concourse Versions

7 component(s)
Fixed Versions:
6.4.16.3.10.0.0-20200730150203-821b48abfd880.0.0-20200730151558-b00d1c8d85761.6.1-0.20200730151558-b00d1c8d8576
Product / Package Ecosystem Affected Versions Fixed Version
github.com/concourse/concourse
Go
≥ 6.4.0
< 6.4.1
All 1 versions
6.4.0
6.4.1
github.com/concourse/concourse
Go
≥ 1.6.1
< 6.3.1
6.3.1
github.com/concourse/dex
Go
≥ 6.4.0
< 6.4.1
All 1 versions
6.4.0
6.4.1
github.com/concourse/dex
Go
≥ 0.0.0
< 6.3.1
6.3.1
github.com/concourse/dex
Go
< 0.0.0-20200730150203-821b48abfd88
0.0.0-20200730150203-821b48abfd88
github.com/concourse/concourse
Go
< 0.0.0-20200730151558-b00d1c8d8576
0.0.0-20200730151558-b00d1c8d8576
github.com/concourse/concourse
Go
≥ 0.0.0
< 1.6.1-0.20200730151558-b00d1c8d8576
1.6.1-0.20200730151558-b00d1c8d8576

References

Frequently Asked Questions

What is CVE-2020-5415?
CVE-2020-5415 is a security vulnerability in Github.com/concourse/concourse involving GitLab auth uses full name instead of username as user ID, allowing impersonation under CWE-290: Authentication Bypass by Spoofing.
Which Github.com/concourse/concourse versions are affected?
Affected versions include releases prior to 6.4.1, 6.3.1, 0.0.0-20200730150203-821b48abfd88, 0.0.0-20200730151558-b00d1c8d8576, 1.6.1-0.20200730151558-b00d1c8d8576 across affected packages: github.com/concourse/concourse, github.com/concourse/dex.
What version fixes CVE-2020-5415?
Upgrading to 6.4.1, 6.3.1, 0.0.0-20200730150203-821b48abfd88, 0.0.0-20200730151558-b00d1c8d8576, 1.6.1-0.20200730151558-b00d1c8d8576 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/concourse/concourse affected?
Yes, github.com/concourse/concourse is affected in releases prior to 6.4.1, 6.3.1, 0.0.0-20200730151558-b00d1c8d8576, 1.6.1-0.20200730151558-b00d1c8d8576. Upgrade your dependency to 6.4.1, 6.3.1, 0.0.0-20200730151558-b00d1c8d8576, 1.6.1-0.20200730151558-b00d1c8d8576 or later.
Is github.com/concourse/dex affected?
Yes, github.com/concourse/dex is affected in releases prior to 6.4.1, 6.3.1, 0.0.0-20200730150203-821b48abfd88. Upgrade your dependency to 6.4.1, 6.3.1, 0.0.0-20200730150203-821b48abfd88 or later.
What is the CVSS score of CVE-2020-5415?
CVE-2020-5415 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2020-5415?
CVE-2020-5415 is classified under CWE-290: Authentication Bypass by Spoofing (This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.).
How can I check Go dependencies for CVE-2020-5415?
Run the dependency tree command: 'inspect dependencies for github.com/concourse/concourse'. 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
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  "id" : "GHSA-627p-rr78-99rj",
  "modified" : "2025-07-22T16:13:01Z",
  "published" : "2021-12-20T17:56:03Z",
  "aliases" : [ "CVE-2020-5415" ],
  "summary" : "GitLab auth uses full name instead of username as user ID, allowing impersonation",
  "details" : "### Impact\n\nInstallations which use the GitLab auth connector are vulnerable to identity spoofing by way of configuring a GitLab account with the same full name as another GitLab user who is granted access to a Concourse team by having their full name listed under `users` in the team configuration or given to the `--gitlab-user` flag.\n\nSee the [GitLab auth docs](https://concourse-ci.org/gitlab-auth.html) for details.\n\nConcourse installations which do not configure the GitLab auth connector are not affected.\n\n### Patches\n\nConcourse [v6.3.1](https://github.com/concourse/concourse/releases/tag/v6.3.1) and [v6.4.1](https://github.com/concourse/concourse/releases/tag/v6.4.1) were both released with a fix on August 4th, 2020.\n\nBoth versions change the GitLab connector to use the username, rather than the full name. This was always the intent, and the previous behavior was originally reported as a bug (concourse/dex#7) prior to being reported as a security issue.\n\nAny Concourse teams which configure GitLab users will have to switch each user from their full name to their username upon upgrading to these versions.\n\n### Workarounds\n\nGitLab groups do not have this vulnerability, so GitLab users may be moved into groups which are then configured in the Concourse team.\n\n### References\n\n* concourse/dex#12: PR with the fix\n\n### For more information\n\nIf you have any questions or comments about this advisory, you may reach us privately at [concourseteam+security@gmail.com](mailto:concourseteam+security@gmail.com).",
  "severity" : [ {
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  }, {
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}