GHSA-vhvq-fv9f-wh4q LookupResources Cursor section tampering can crash SpiceDB process via tuple.MustParse panic
An attacker with a valid token can crash the SpiceDB server by sending a malformed cursor token, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is GHSA-vhvq-fv9f-wh4q?
GHSA-vhvq-fv9f-wh4q is a denial of service vulnerability in github.com/authzed/spicedb, published on 6 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Description
A malformed or tampered-with LookupResources Cursor token can cause a panic in the SpiceDB process if it fails to parse. If an attacker were able to make requests to a SpiceDB instance, they could affect its availability.
Reproduction
If one was to take a cursor from a LookupResources call, decode it according to the logic that SpiceDB uses, and modify the Sections field to include an invalid relationship string, the process will panic.
Impact
An attacker would need both the ability to create a gRPC connection to your SpiceDB instance and a valid token, or else the ability to pass a cursor token from outside your application through to your SpiceDB instance.
If an attacker had this ability, they could bring down SpiceDB instances, reducing the availability of SpiceDB and any service that depends on it.
Mechanism
The SpiceDB process does not validate the contents of this Sections component of the Cursor message. In affected versions, it uses a parsing function that calls panic if the value cannot be parsed as a relationship.
Fix
This issue was fixed in https://github.com/authzed/spicedb/pull/2878.
Remediations
- Prevent client control of the
optional_cursorfield inLookupResourcescalls - Upgrade to an unaffected version
Which versions are affected by GHSA-vhvq-fv9f-wh4q?
3 open source packages ship an affected version, including github.com/authzed/spicedb.
| Package | Affected | Fixed in |
|---|---|---|
github.com/authzed/spicedb Go | All versions | 1.49.1 |
github.com/authzed/spicedb Go | From 1.29.3 | 1.49.1 |
github.com/authzed/spicedb Go | From 1.29.3 | 1.49.1 |
How do I fix GHSA-vhvq-fv9f-wh4q?
Upgrade github.com/authzed/spicedb to 1.49.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is GHSA-vhvq-fv9f-wh4q being exploited?
There is no known exploitation of GHSA-vhvq-fv9f-wh4q in the wild and no public exploit code.
Sources
Also known as GO-2026-4465.