CVE-2026-78806 Overview
CVE-2026-78806 is an information disclosure vulnerability in the Matter Standard Specification implementation, specifically the Matter Project CHIP (Connected Home over IP) v1.5.1. The flaw resides in the PerformCommissioningStep function within the ChipDeviceController.cpp component. A local attacker with low privileges can leverage this issue to obtain sensitive information from the commissioning process. The vulnerability is categorized as [CWE-200] Exposure of Sensitive Information to an Unauthorized Actor.
Critical Impact
Local low-privileged actors can extract sensitive commissioning data from Matter smart-home devices running CHIP v1.5.1, undermining confidentiality of onboarding secrets.
Affected Products
- Matter Standard Specification v1.5.1
- Matter Project CHIP (Connected Home over IP) v1.5.1
- ChipDeviceController.cpp component invoking PerformCommissioningStep
Discovery Timeline
- 2026-09-21 - CVE-2026-78806 published to NVD
- 2026-09-24 - Last updated in NVD database
Technical Details for CVE-2026-78806
Vulnerability Analysis
The defect exists in the commissioning workflow of the Matter reference implementation (Project CHIP). During commissioning, the PerformCommissioningStep function in ChipDeviceController.cpp orchestrates the exchange of setup credentials, network provisioning data, and operational certificates between a commissioner and a commissionee. The implementation gap allows a local attacker to observe sensitive artifacts produced or handled during these steps.
Because the flaw affects confidentiality only, integrity and availability of the Matter device remain intact. However, disclosed commissioning material can facilitate follow-on attacks against the fabric, including impersonation or unauthorized enrollment of rogue devices.
Root Cause
The root cause is a specification-to-implementation gap in Matter v1.5.1. The PerformCommissioningStep routine does not enforce the confidentiality controls described by the Matter Standard Specification for intermediate commissioning state. Sensitive values remain accessible to local, low-privileged processes rather than being isolated to the commissioning context.
Attack Vector
Exploitation requires local access and low privileges on the host executing the CHIP controller. No user interaction is needed. An attacker running code on the commissioner device can query or read state associated with PerformCommissioningStep and recover sensitive commissioning information. Full technical details are available through the GitHub Connected Home IP Project and the CSA IoT Specification Request portal.
No public proof-of-concept exploit is currently listed for this CVE. Refer to the GitHub Matter Repository referenced by the reporter for additional context.
Detection Methods for CVE-2026-78806
Indicators of Compromise
- Unexpected local processes reading memory or files belonging to the CHIP controller process during device commissioning windows.
- Access to commissioning artifacts or logs generated by ChipDeviceController.cpp from accounts unrelated to the commissioning workflow.
- Anomalous invocations or tracing of the PerformCommissioningStep function on hubs, gateways, or mobile controllers.
Detection Strategies
- Enable verbose logging on the CHIP commissioner and monitor for repeated or out-of-band calls into commissioning routines.
- Inspect endpoint telemetry for local privilege boundary crossings around Matter controller binaries and their data directories.
- Correlate device onboarding events with process, file, and memory access telemetry to identify unauthorized readers.
Monitoring Recommendations
- Track commissioning frequency and duration on Matter hubs; investigate unexpected re-commissioning events.
- Alert on any non-commissioner process opening handles to CHIP controller state, credential caches, or fabric storage.
- Retain host telemetry for the commissioning window to support forensic review if disclosure is suspected.
How to Mitigate CVE-2026-78806
Immediate Actions Required
- Restrict local access to devices running Matter CHIP v1.5.1 controllers, particularly during device commissioning.
- Perform commissioning only on trusted hosts with hardened user separation and up-to-date OS patches.
- Audit local accounts and running services on commissioners to remove unnecessary low-privileged users.
Patch Information
No vendor patch is referenced in the NVD entry for CVE-2026-78806 at the time of publication. Monitor the GitHub Connected Home IP Project repository and Connectivity Standards Alliance advisories for updates addressing the PerformCommissioningStep implementation gap in v1.5.1.
Workarounds
- Isolate the commissioner host on a dedicated management network segment during onboarding.
- Disable or remove untrusted local applications on devices used to commission Matter fabrics.
- Rotate any commissioning credentials, setup codes, or fabric certificates if disclosure is suspected.
# Configuration example
# Restrict access to the CHIP controller working directory on Linux hosts
sudo chown root:matter /var/lib/chip
sudo chmod 750 /var/lib/chip
# Ensure only the commissioning service account can read commissioning state
sudo setfacl -m u:matter:r-x /var/lib/chip
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.