SpiceDB: Checks involving relations with caveats can result in unconditional permission when conditional permission is expected

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

3.7 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS

• CVE-2026-55866: 0.34% estimated exploitation activity in the next 30 days; percentile 27.70 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Under concurrency, CheckPermission and CheckBulkPermissions can return PERMISSIONSHIPHASPERMISSION for a (resource, permission, subject) whose correct answer is PERMISSIONSHIPCONDITIONALPERMISSION. 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: 2. A subject reaches the permission via the caveated edge: 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, haspermission, user:caveatedreader) → HASPERMISSION (incorrect; should be CONDITIONALPERMISSION) CheckPermission(document:firstdoc, haspermission, user:caveatedreader, context =…

Published by the source

19 Jun 2026, 21:42 UTC

Last modified by the source

23 Jun 2026, 17:17 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-4vrg-r928-h5vv

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# Patch Next advisory brief: CVE-2026-55866

Advisory: SpiceDB: Checks involving relations with caveats can result in unconditional permission when conditional permission is expected
IDs: CVE-2026-55866, GHSA-4vrg-r928-h5vv
Record: https://patchnext.com/advisories/cve-2026-55866 (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/authzed/spicedb 1.54.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/authzed/spicedb: affected >= 1.34.0, < 1.54.0; fixed in 1.54.0

## Suggested inspection (read-only)
- Go github.com/authzed/spicedb: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/authzed/spicedb.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-4vrg-r928-h5vv (GitHub-reviewed advisory GHSA-4vrg-r928-h5vv lists affected ranges: Go github.com/authzed/spicedb >=1.34.0 <1.54.0)

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