CVE-2026-31499
Description
A flaw was found in the Linux kernel's Bluetooth L2CAP component. A deadlock can occur in the l2cap_conn_del() function when canceling delayed work, specifically info_timer and id_addr_timer. This happens because l2cap_conn_del() holds a lock while attempting to cancel work functions that also acquire the same lock, creating a circular waiting condition. This concurrency issue can lead to a Denial of Service (DoS), making the system unresponsive.
Statement
Red Hat acknowledges the AB-BA deadlock between conn->lock and delayed work cancellation fixed by reordering to disable_delayed_work_sync() before taking the lock. Impact is availability for systems actively tearing down L2CAP connections. Patch via kernel errata; Bluetooth unload remains an operational workaround.
Mitigation
To mitigate this issue, prevent the bluetooth module from being loaded. See https://access.redhat.com/solutions/41278 for instructions.
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 | 5.5 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Other); DoS: Crash, Exit, or Restart
Each thread of execution will "hang" and prevent tasks from completing. In some cases, CPU consumption may occur if a lock check occurs in a tight loop.
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