CVE-2026-13699: Eclipse Kuksa Databroker DoS Vulnerability

CVE-2026-13699 Overview

CVE-2026-13699 affects Eclipse KUKSA Databroker version 0.6.1, an open-source vehicle data broker used in connected vehicle and IoT deployments. The kuksa.val.v2.VAL/PublishValue gRPC handler fails to validate the optional data_point field in PublishValueRequest. When an authenticated client submits a request with a valid signal_id but omits data_point, the server calls unwrap() on the missing field, triggering a panic in the Tokio worker thread. The panic cancels the individual gRPC call but does not terminate the Databroker process. Any client holding a valid JSON Web Token (JWT) can trigger the condition, creating a repeatable availability impact against automotive data pipelines.

Critical Impact
Authenticated attackers with a valid JWT can repeatedly panic Tokio worker threads in the Eclipse KUKSA Databroker, degrading availability of vehicle signal processing.

Affected Products

Eclipse KUKSA Databroker 0.6.1
Deployments exposing the kuksa.val.v2.VAL gRPC service
Connected vehicle and IoT stacks integrating KUKSA for signal brokering

Discovery Timeline

2026-07-14 - CVE-2026-13699 published to NVD
2026-07-14 - Last updated in NVD database

Technical Details for CVE-2026-13699

Vulnerability Analysis

The flaw is an input validation defect [CWE-20] in the gRPC service layer of Eclipse KUKSA Databroker. The PublishValue handler treats the data_point field of PublishValueRequest as optional at the Protocol Buffers layer but as required in the Rust implementation. When the field is absent, the handler invokes unwrap() on the Option, which panics inside the Tokio async runtime.

The panic is contained to the worker thread handling the request. The Databroker process remains alive and continues to serve other clients. Repeated exploitation forces continuous thread panics, wastes CPU cycles on stack unwinding, and disrupts legitimate signal publication workflows.

Root Cause

The root cause is missing validation of an optional Protobuf field before dereferencing it. Rust's Option::unwrap() is a fail-fast primitive intended for values guaranteed to be present. Using it on untrusted client input violates safe-handling patterns and converts a malformed request into a thread panic instead of a graceful gRPC error response.

Attack Vector

Exploitation requires network reachability to the Databroker gRPC endpoint and a valid JWT. Unauthenticated requests and requests with invalid tokens are rejected before reaching the vulnerable code path. Any legitimate client, compromised credential, or lower-privilege service account with publish rights can send crafted PublishValueRequest messages omitting data_point to trigger the panic on demand.

The vulnerability is described in prose because no verified public proof-of-concept code is available. See the Eclipse Security CVE Assignment for upstream details.

Detection Methods for CVE-2026-13699

Indicators of Compromise

Tokio worker thread panic messages referencing unwrap() on PublishValueRequest.data_point in Databroker logs
Elevated volume of cancelled gRPC calls to kuksa.val.v2.VAL/PublishValue from a single authenticated principal
Repeated PublishValueRequest messages containing only signal_id without a data_point payload

Detection Strategies

Parse Databroker stderr and structured logs for panic stack traces originating in the PublishValue handler.
Correlate gRPC status codes on the VAL service with authenticated client identity extracted from JWT claims.
Deploy a gRPC-aware inspection proxy to flag PublishValueRequest payloads that omit data_point.

Monitoring Recommendations

Alert on any thread panic events emitted by the Databroker process, regardless of frequency.
Track per-client error rates on the kuksa.val.v2.VAL/PublishValue endpoint and threshold on abnormal spikes.
Monitor JWT issuance and revocation events to identify tokens generating disproportionate malformed requests.

How to Mitigate CVE-2026-13699

Immediate Actions Required

Restrict network access to the Databroker gRPC port to trusted vehicle subsystems and management planes.
Audit issued JWTs and revoke tokens granted to non-essential or third-party clients.
Enable process supervision so any Databroker crash triggers automatic restart, even though the current defect does not terminate the process.

Patch Information

No fixed version is referenced in the published advisory at the time of writing. Monitor the Eclipse Security CVE Assignment and the upstream Eclipse KUKSA repository for a release addressing the missing validation in the PublishValue handler.

Workarounds

Place a gRPC proxy or service mesh policy in front of Databroker that rejects PublishValueRequest messages missing data_point.
Reduce the scope of JWT publish claims so only vetted producers can call kuksa.val.v2.VAL/PublishValue.
Shorten JWT lifetimes and enforce mutual TLS to limit the window for token abuse.

bash

# Example Envoy gRPC-JSON transcoding filter rejecting requests without data_point
# Apply as an ext_authz or Lua filter in front of the KUKSA Databroker
function envoy_on_request(request_handle)
  local body = request_handle:body()
  if body and not string.find(tostring(body:getBytes(0, body:length())), "data_point") then
    request_handle:respond(
      {[":status"] = "400"},
      "PublishValueRequest missing required data_point"
    )
  end
end