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Exclusions under arrows with multiple resources can result in no permission returned when permission expected

Low
josephschorr published GHSA-grjv-gjgr-66g2 Jun 20, 2024

Package

gomod github.com/authzed/spicedb (Go)

Affected versions

<v1.33.1

Patched versions

v1.33.1

Description

Background

Use of an exclusion under an arrow that has multiple resources may resolve to NO_PERMISSION when permission is expected.

For example, given this schema:

definition user {}

definition folder {
  relation member: user
  relation banned: user
  permission view = member - banned
}

definition resource {
  relation folder: folder
  permission view = folder->view
}

If the resource exists under multiple folders and the user has access to view more than a single folder, SpiceDB may report the user does not have access due to a failure in the exclusion dispatcher to request that all the folders in which the user is a member be returned

Impact

Permission is returned as NO_PERMISSION when PERMISSION is expected on the CheckPermission API.

Workarounds

None

Severity

Low

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

CVE ID

CVE-2024-38361

Weaknesses

No CWEs