Security readout for executives and security teams
Plain-English summary
Concourse could mistake one GitLab user for another when teams granted access through the GitLab auth connector using user identity. A person with a matching GitLab full name could be treated as an authorized team member. This threatens confidentiality and integrity of CI/CD environments, especially where Concourse controls deployments or secrets.
Executive priority
Treat this as urgent for any affected Concourse deployment, because CI/CD identity spoofing can expose source, secrets, pipelines, and deployment authority. Prioritize internet-accessible or production-linked Concourse systems first.
Technical view
CVE-2020-5415 is an identity spoofing flaw in Concourse before 6.3.1 and 6.4.1 when using the GitLab auth connector. The issue is tied to GitLab account full-name matching for team access. CVSS is 10.0 with network attack vector, low complexity, no privileges, no user interaction, and scope changed.
Likely exposure
Exposure is limited to Concourse 6.3 or 6.4 installations before 6.3.1 or 6.4.1 that use the GitLab auth connector. The source states GitLab groups do not have this vulnerability.
Exploitation context
The bundle does not cite active exploitation, and KEV status is false. Public sources describe a critical, low-complexity spoofing path, but no exploit activity or weaponized tooling is provided in the supplied evidence.
Researcher notes
The key exposure condition is GitLab auth connector usage with user-based team authorization. The provided sources identify fixed version boundaries and a group-based mitigation, but do not provide evidence of exploitation in the wild.
Mitigation direction
- Upgrade affected Concourse deployments to 6.3.1, 6.4.1, or later vendor-supported versions.
- Move GitLab users into GitLab groups and configure Concourse teams against those groups.
- Review Concourse team access rules that depend on individual GitLab users.
- Check current vendor advisories before deployment or emergency change decisions.
Validation and detection
- Inventory Concourse versions and identify deployments using the GitLab auth connector.
- Confirm no affected deployment remains below 6.3.1 or 6.4.1.
- Review Concourse teams for individual GitLab user grants instead of group-based grants.
- Audit recent team access for unexpected GitLab identities or duplicate full-name patterns.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-290: Exact CWE lookup
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Open ATT&CK lookupCVE-2020-5415 mapping review
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Open ATT&CK lookup- Severity
- Critical
- CVSS
- 10 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L3.96Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
10CriticalVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/concourse/concourse/security/advisories/GHSA-627p-rr78-99rjCVE reference · x_refsource_CONFIRM
- https://tanzu.vmware.com/security/cve-2020-5415CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Authentication Bypass by Spoofing
Authentication Bypass by Spoofing represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.