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GHSA-4vrg-r928-h5vv

LowCVSS 3.7 / 10
Published Jun 19, 2026·Last modified Jun 19, 2026
Affected Components(0)

No affected components available

Description

Impact

Under concurrency, CheckPermission and CheckBulkPermissions can return PERMISSIONSHIP_HAS_PERMISSION for a (resource, permission, subject) whose correct answer is PERMISSIONSHIP_CONDITIONAL_PERMISSION.

You are impacted if all of the following hold:

  1. Your schema has a permission combining relations with an intersection or exclusion, where a subject reaches it through a caveated branch and a non-caveated branch. For example:
  definition user {}

  caveat some_caveat(somecondition int) { somecondition == 42 }

  definition document {
    relation reader: user | user with some_caveat
    relation writer: user
    relation banned: user
    permission has_permission = (reader & writer) - banned
  }
  1. A subject reaches the permission via the caveated edge:
  document:firstdoc#reader@user:caveatedreader[some_caveat]
  document:firstdoc#writer@user:caveatedreader
  1. Your workload issues LookupResources with a context request parameter, concurrently with CheckPermission/CheckBulkPermissions for the same subject/resource, and
  2. The dispatch result cache is enabled.

When all of the above are true, there is an intermittent window in which:

CheckPermission(document:firstdoc, has_permission, user:caveatedreader) → HAS_PERMISSION (incorrect; should be CONDITIONAL_PERMISSION)

CheckPermission(document:firstdoc, has_permission, user:caveatedreader, context = {"somecondition": 41}) → HAS_PERMISSION (incorrect; should be NO_PERMISSION)

Patches

v1.54.0

Workarounds

Disable the dispatch result cache (ClusterDispatchCacheConfig and DispatchCacheConfig)

Risk Scores
Base Score
3.7

The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the integrity of the data.

Threat Intelligence
3.4

Limited exploitation activity has been observed. Close monitoring and planned remediation are recommended.

EPSS
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Related Vulnerabilities
  • CVE-2026-55866
    Alias

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Low severity
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