CVE-2026-63735 is a high-severity (CVSS 8.1) CWE-639 vulnerability in surrealdb. A fix is available for surrealdb — see the affected versions and patch details below.
SurrealDB: Custom API route lets authenticated callers override namespace/database scope via URL path
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-63735.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-63735 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 391,411 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
surrealdbReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
An authenticated user scoped to one namespace/database could invoke a custom API (DEFINE API) belonging to a different namespace/database, reaching another tenant's endpoint.
The route /api/{namespace}/{database}/{endpoint} took the namespace and database from the URL and applied them to the caller's session before the endpoint was looked up or run, without checking that the caller's authenticated scope covered them. Because a custom API handler runs with permissions disabled (definer's rights), the endpoint's own PERMISSIONS clause was the only gate — open to everyone for a PERMISSIONS FULL endpoint. The api::invoke() function was affected the same way, resolving against the session's selected namespace/database (settable via the surreal-ns / surreal-db headers or USE).
Impact
What an attacker can do:
- With valid credentials for any one namespace/database (a
VIEWERis enough), invoke a custom API in another namespace/database by naming the victim scope in the URL. - Read data that endpoint returns — including from
PERMISSIONS NONEtables, since the handler runs with permissions disabled — or trigger any writes and side effects it performs.
What it can't do:
- Reach a scope without valid credentials for some namespace/database on the instance; this is not an unauthenticated bypass.
- Affect single-tenant deployments, or any deployment where callers already hold instance-wide (root) scope.
Patches
The namespace/database is now validated against the caller's authenticated level — which the request cannot change — before the endpoint is resolved or run. A target scope outside that level is rejected with 403 Forbidden, both at the HTTP entry point and at the dispatch step shared with api::invoke(). Root reaches any scope; namespace principals their namespace; database and record principals their exact namespace/database; anonymous callers remain governed by the endpoint's PERMISSIONS.
- Versions 3.2.0 and later are not affected by this issue.
Workarounds
Users unable to patch should consider the following workarounds:
- Disable the custom API HTTP route via capabilities where it is not required.
- Treat separate deployments, not namespace/database boundaries, as the tenant isolation boundary on shared instances.
- Prefer a
PERMISSIONS WHEREclause that checks the authenticated identity overPERMISSIONS FULL(reduces exposure but does not restore the boundary).
Resources
- SurrealQL Documentation — DEFINE API
- SurrealDB Documentation — Capabilities
fix(core/api): reject cross-tenant custom API access(included in SurrealDB 3.2.0)
Acknowledgements
SurrealDB thanks sondt99 for reporting this issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | surrealdb | all versions | 3.2.0cargo update -p surrealdb --precise 3.2.0 |
Affected Products
surrealdbsurrealdbDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for surrealdb, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update surrealdb to 3.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-63735 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2026-63735 in your dependencies?
Find it across crates.io, including transitive dependencies.