CVE-2026-55866: SpiceDB Checks Involving Relations With Caveats Vulnerability

LOW
Advisory Identifier: GHSA-4vrg-r928-h5vv
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CVSS 3.7
CWE-863
Published
Advisory Summary

CVE-2026-55866 is a LOW (CVSS 3.7) checks involving relations with caveats vulnerability (CWE-863: Incorrect Authorization) affecting SpiceDB libraries in the Go ecosystem. The issue involves checks involving relations with caveats can result in unconditional permission when conditional permission is expected. Remediation is available by upgrading affected packages to version 1.54.0.

CVE-2026-55866 at a Glance

CVE Identifier CVE-2026-55866
GHSA Identifier GHSA-4vrg-r928-h5vv
Severity LOW
CVSS v3.1 Base Score 3.7
CWE Classification CWE-863: Incorrect Authorization
Affected Product SpiceDB
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 3.7

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-55866

To remediate this vulnerability, upgrade all affected SpiceDB 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/authzed/spicedb fixed: 1.54.0 
Upgrade github.com/authzed/spicedb to 1.54.0
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/authzed/spicedb

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-55866, inspect your project dependencies for SpiceDB:

inspect dependencies for github.com/authzed/spicedb

Analyze the terminal output to locate any version of SpiceDB in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.54.0), 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-863: Incorrect Authorization, where the product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. In SpiceDB, 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 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: ```zed 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 } ``` 2. A subject reaches the permission via the caveated edge: ``` document:firstdoc#reader@user:caveatedreader[some_caveat] document:firstdoc#writer@user:caveatedreader ``` 3. Your workload issues `LookupResources` with a `context` request parameter, concurrently with `CheckPermission/CheckBulkPermissions` for the same subject/resource, and 4. 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`)

CVE-2026-55866 Affected SpiceDB Versions

1 component(s)
Fixed Versions:
1.54.0
Product / Package Ecosystem Affected Versions Fixed Version
github.com/authzed/spicedb
golang/github.com/authzed/spicedb
Go
≥ 1.34.0
< 1.54.0
1.54.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/authzed/spicedb/security/advisories/GHSA-4vrg-r928-h5vv
SpiceDB Source Repository REPOSITORY
https://github.com/authzed/spicedb

Frequently Asked Questions

What is CVE-2026-55866?
CVE-2026-55866 is a security vulnerability in SpiceDB involving Checks involving relations with caveats can result in unconditional permission when conditional permission is expected under CWE-863: Incorrect Authorization.
Which SpiceDB versions are affected?
Affected versions include releases prior to 1.54.0 across affected packages: github.com/authzed/spicedb.
What version fixes CVE-2026-55866?
Upgrading to 1.54.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/authzed/spicedb affected?
Yes, github.com/authzed/spicedb is affected in releases prior to 1.54.0. Upgrade your dependency to 1.54.0 or later.
What is the CVSS score of CVE-2026-55866?
CVE-2026-55866 has a CVSS v3.1 base score of 3.7 (LOW) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N.
What CWE is associated with CVE-2026-55866?
CVE-2026-55866 is classified under CWE-863: Incorrect Authorization (The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.).
How can I check Go dependencies for CVE-2026-55866?
Run the dependency tree command: 'inspect dependencies for github.com/authzed/spicedb'. 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-4vrg-r928-h5vv",
  "modified" : "2026-06-19T21:42:12Z",
  "published" : "2026-06-19T21:42:12Z",
  "aliases" : [ "CVE-2026-55866" ],
  "summary" : "SpiceDB: Checks involving relations with caveats can result in unconditional permission when conditional permission is expected",
  "details" : "### Impact\n Under concurrency, `CheckPermission` and `CheckBulkPermissions` can return `PERMISSIONSHIP_HAS_PERMISSION` for a (resource, permission, subject) whose correct answer is   `PERMISSIONSHIP_CONDITIONAL_PERMISSION`. \n\n You are impacted if **all** of the following hold:\n\n  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:\n\n```zed\n  definition user {}\n\n  caveat some_caveat(somecondition int) { somecondition == 42 }\n\n  definition document {\n    relation reader: user | user with some_caveat\n    relation writer: user\n    relation banned: user\n    permission has_permission = (reader & writer) - banned\n  }\n```\n\n  2. A subject reaches the permission via the caveated edge:\n\n```\n  document:firstdoc#reader@user:caveatedreader[some_caveat]\n  document:firstdoc#writer@user:caveatedreader\n```\n  3. Your workload issues `LookupResources` with a `context` request parameter, concurrently with `CheckPermission/CheckBulkPermissions` for the same subject/resource, and\n  4. The dispatch result cache is enabled.\n  \nWhen all of the above are true, there is an intermittent window in which:\n\n`CheckPermission(document:firstdoc, has_permission, user:caveatedreader)` → HAS_PERMISSION (incorrect; should be CONDITIONAL_PERMISSION)\n\n`CheckPermission(document:firstdoc, has_permission, user:caveatedreader, context = {\"somecondition\": 41})` → HAS_PERMISSION (incorrect; should be NO_PERMISSION)\n\n### Patches\n\nv1.54.0\n\n### Workarounds\nDisable the dispatch result cache (`ClusterDispatchCacheConfig` and `DispatchCacheConfig`)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/authzed/spicedb"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.34.0"
      }, {
        "fixed" : "1.54.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/authzed/spicedb/security/advisories/GHSA-4vrg-r928-h5vv"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/authzed/spicedb"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-863" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-19T21:42:12Z",
    "nvd_published_at" : null
  }
}