CVE 설명

The Bluetooth Classic AVDTP layer defers releasing a session's stream endpoints: bt_avdtp_l2cap_disconnected() in subsys/bluetooth/host/classic/avdtp.c ends with k_work_submit(&session->_release_work), placing the embedded struct k_work on the system work queue's pending list. When the same struct bt_avdtp object is immediately reused for a new signalling connection, the session memory is re-initialized — a2dp_get_connection() in subsys/bluetooth/host/classic/a2dp.c memset()s the whole struct bt_a2dp, and bt_avdtp_l2cap_accept() / bt_avdtp_connect() call k_work_init() on session->_release_work — while that work item is still linked into k_sys_work_q.pending. Zeroing a linked sys_snode_t truncates the list while its tail pointer keeps pointing past the truncation. The reuse window is deterministic rather than a race. All host RX processing runs on the Bluetooth RX work queue at a cooperative priority (CONFIG_BT_RX_PRIO), while _release_work is submitted to the lower-priority system work queue, so the release handler cannot run until the RX thread blocks. Because l2cap_br_recv() processes every signalling command contained in a single L2CAP signalling PDU back-to-back, a peer can send one PDU holding an L2CAP Disconnection Request for the AVDTP signalling channel followed by a Connection Request for PSM 0x0019; the second command reaches the session-reuse path with the release work provably still queued. The peer must already hold an encrypted AVDTP signalling channel, i.e. be a paired/bonded BR/EDR device. The result is corruption of the global system work queue's pending list: either the queue silently stops executing any work at all (subsequent submissions are appended to a chain the head can no longer reach, and the orphaned items keep their K_WORK_QUEUED flag forever) or, in the tail variant, the list acquires a self-referencing node that the queue thread spins on. The written values are pointers to other struct k_work objects and are not attacker-controlled, so the impact is a device-wide, reboot-required denial of service rather than a controllable write primitive. Only builds with CONFIG_BT_CLASSIC and CONFIG_BT_A2DP are affected. The fix is a two-commit unit, and neither commit closes the path on its own. ec822ceed83b adds a pending-release check to bt_avdtp_connect() and bt_avdtp_l2cap_accept(), but the A2DP upper layer's a2dp_get_connection() memset()s the session — including the queued work item's list node and flags — before those checks run, so k_work_busy_get() would observe an already-cleared state. 2bd5ea88c69b closes that by making a2dp_get_connection() itself skip the reuse and return NULL while the release work is still pending, which both callers already handle by rejecting the connection attempt. Apply both commits together; either one alone leaves the device vulnerable.

CVE 정보

관련 약점

CWE-ID	약점 이름	출처
CWE-666	Operation on Resource in Wrong Phase of Lifetime The product performs an operation on a resource at the wrong phase of the resource's lifecycle, which can lead to unexpected behaviors.

메트릭

메트릭	점수	심각도	CVSS 벡터	출처
V3.1	5.7	MEDIUM	CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H 추가 정보 Base: Exploitabilty Metrics The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component. Attack Vector This metric reflects the context by which vulnerability exploitation is possible. Adjacent The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone). Attack Complexity This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability. Low Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component. Privileges Required This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability. Low The attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources. User Interaction This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component. None The vulnerable system can be exploited without interaction from any user. Base: Scope Metrics The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope. Scope Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs. Unchanged An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority. Base: Impact Metrics The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve. Confidentiality Impact This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability. None There is no loss of confidentiality within the impacted component. Integrity Impact This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. None There is no loss of integrity within the impacted component. Availability Impact This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. High There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable). Temporal Metrics The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence in the description of a vulnerability. Environmental Metrics These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.	vulnerabilities@zephyrproject.org