# 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.

- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Sep 2026
- **Updated:** 14 Sep 2026
- **Also known as:** GHSA-4vrg-r928-h5vv, GO-2026-5133

## 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 (Incorrect Authorization)

## Which versions are affected by CVE-2026-55866?

3 open source packages ship an affected version, including github.com/authzed/spicedb.


| Package | Ecosystem | 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55866 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-55866 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/authzed/spicedb (Go): affected from 1.34.0; fixed in 1.54.0
- github.com/authzed/spicedb (Go): affected from 1.34.0; fixed in 1.54.0
- github.com/authzed/spicedb (Go): affected from 1.34.0; fixed in 1.54.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-55866/ (Markdown: https://insights.sbomify.com/CVE-2026-55866/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55866
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55866
- OSV: https://osv.dev/vulnerability/CVE-2026-55866

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55866/
Summaries are generated and may contain mistakes; the official description above is the record.