Highly exploitable, CVE-2026-10685 poses a critical security risk that could lead to severe breaches.
Status: Received on 31 Jul 2026, 15:16 UTC
Published on: 31 Jul 2026, 15:16 UTC
CVSS Release: version 3
vulnerabilities@zephyrproject.org
Secondary
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
CVE-2026-10685: The Zephyr Bluetooth GATT client CCC-write response handler gatt_write_ccc_rsp() in subsys/bluetooth/host/gatt.c invoked the application's params->subscribe() callback after it had already called params->notify(conn, params, NULL, 0). Per the public GATT API, a notify callback with NULL data is the documented signal that the subscription has terminated and the bt_gatt_subscribe_params struct may be freed or reused by the application; calling subscribe() on the struct afterwards is a use-after-free, including an indirect call through the freed params->subscribe function pointer. The error branch is remotely (adjacent) reachable: a Zephyr device acting as a GATT client that calls bt_gatt_subscribe() can be driven into this ordering when a connected GATT server peer answers the CCC write with an ATT Error Response (the peer-supplied error code flows through att_error_rsp -> att_handle_rsp into gatt_write_ccc_rsp). For applications that free or recycle subscription parameters in their notification-termination handler, this results in memory corruption, a crash (denial of service), or potentially attacker-influenced control flow. The fix reorders the handler so the subscribe() callback runs before the terminating notify(NULL) in both the error and unsubscribe paths.
The exploitability of CVE-2026-10685 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
With low attack complexity and no required privileges, CVE-2026-10685 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2026-10685, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2026-10685, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
Stay updated with real-time CVE vulnerabilities and take action to secure your systems. Enhance your cybersecurity posture with the latest threat intelligence and mitigation techniques. Develop the skills necessary to defend against CVEs and secure critical infrastructures. Join the top cybersecurity professionals safeguarding today's infrastructures.