CVE-2026-55866 SpiceDB: Checks involving relations with caveats can result in unconditional permission when conditional permission is expected
SpiceDB may grant unconditional permission instead of conditional permission due to cache poisoning, allowing unauthorized access when specific concurrency and configuration conditions are met.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55866?
CVE-2026-55866 is a low-severity vulnerability in authzed spicedb, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
SpiceDB is an open source database system for creating and managing security-critical application permissions. From 1.34.0 until 1.54.0, SpiceDB can return PERMISSIONSHIP_HAS_PERMISSION instead of PERMISSIONSHIP_CONDITIONAL_PERMISSION or PERMISSIONSHIP_NO_PERMISSION because checkRequestToKey() and checkRequestToKeyWithCanonical() in internal/dispatch/keys/computed.go omit CheckHints when constructing dispatch Check cache keys. The incorrect result requires a permission combining relations with intersection or exclusion, a subject reachable through caveated and non-caveated branches, LookupResources with a context parameter running concurrently with CheckPermission or CheckBulkPermissions for the same resource and subject, and an enabled dispatch result cache. Under these conditions, a result computed for one hint set can poison the cache entry used by a semantically different authorization check, allowing permission without satisfying the caveat. This issue is fixed in version 1.54.0.
Weakness: CWE-863
Which versions are affected by CVE-2026-55866?
3 open source packages ship an affected version, including github.com/authzed/spicedb.
| Package | Affected | Fixed in |
|---|---|---|
github.com/authzed/spicedb Go | From 1.34.0 | 1.54.0 |
github.com/authzed/spicedb Go | From 1.34.0 | 1.54.0 |
github.com/authzed/spicedb Go | From 1.34.0 | 1.54.0 |
How do I fix CVE-2026-55866?
Upgrade github.com/authzed/spicedb to 1.54.0 or later.
Is CVE-2026-55866 being exploited?
There is no known exploitation of CVE-2026-55866 in the wild and no public exploit code.
Sources
Also known as GHSA-4vrg-r928-h5vv, GO-2026-5133.