CVE-2026-98734
Description
A flaw was found in the Linux kernel's Bluetooth subsystem. A local attacker could exploit this flaw to cause a Denial of Service (DoS) via a system crash or potentially escalate privileges. The vulnerability occurs due to improper synchronization between packet transmission scheduling and connection teardown, resulting in a use-after-free condition where memory is accessed after being freed.
Statement
A race in the Bluetooth HCI transmit path allows an hci_conn object selected under RCU to be used after the RCU read lock has been released. Concurrent hci_abort_conn_sync execution can remove and free the connection before hci_sched_iso or hci_sched_sco finishes accessing its queues and updating conn sent. KASAN confirms a slab use-after-free, and the later conn sent update may write into reused slab memory. For the CVSS the PR:L reflects that a local user or process must create or operate a Bluetooth SCO or ISO connection, while AC:H reflects the need to hit a narrow race window during connection teardown. The issue is not directly reachable through ordinary IP network traffic. An adjacent Bluetooth peer may influence connection state, but the available evidence does not show a reliable peer-only trigger without local activity. Impact is at least a local denial of service via kernel crash and in the worst case may include confidentiality and integrity impact or privilege escalation due to use-after-free memory corruption.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.7 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory
The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Confidentiality
Technical Impact: Read Memory
Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.
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