In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: fix race l2cap_sock_cleanup_listen() vs. (CVE-2026-90091)
A race condition vulnerability in the Linux kernel's Bluetooth L2CAP socket handling was resolved. The flaw involves unsafe lockless reads in l2cap_sock_cleanup_listen() that can lead to a null pointer dereference due to concurrent operations on L2CAP sockets. The issue was fixed by adding proper locking in l2cap_sock_kill() to synchronize access and prevent the race condition.
AI Analysis
Technical Summary
CVE-2026-90091 addresses a race condition in the Linux kernel Bluetooth L2CAP implementation. Specifically, for L2CAP sockets without an owning sk->sk_socket, reading l2cap_pi(sk)->chan in l2cap_sock_cleanup_listen() can race against concurrent l2cap_sock_kill() calls that nullify this pointer. This unsafe lockless read can cause a null pointer dereference. The fix involves taking the lock_sock() lock in l2cap_sock_kill() to synchronize with l2cap_sock_cleanup_listen(), eliminating the race and preventing the null pointer dereference.
Potential Impact
The vulnerability can cause a null pointer dereference in the Linux kernel Bluetooth stack, potentially leading to denial of service or kernel crashes. The CVSS score of 8.0 indicates high severity with impact on confidentiality, integrity, and availability. No known exploits in the wild have been reported.
Mitigation Recommendations
A fix is available that resolves the race condition by adding proper locking in the kernel Bluetooth L2CAP code. Users should apply the official Linux kernel updates that include this patch to remediate the vulnerability. Since this is a kernel-level issue, updating to a patched kernel version is the recommended mitigation.
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: fix race l2cap_sock_cleanup_listen() vs. (CVE-2026-90091)
Description
A race condition vulnerability in the Linux kernel's Bluetooth L2CAP socket handling was resolved. The flaw involves unsafe lockless reads in l2cap_sock_cleanup_listen() that can lead to a null pointer dereference due to concurrent operations on L2CAP sockets. The issue was fixed by adding proper locking in l2cap_sock_kill() to synchronize access and prevent the race condition.
CVSS v3.1
Score 8.0high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-90091 addresses a race condition in the Linux kernel Bluetooth L2CAP implementation. Specifically, for L2CAP sockets without an owning sk->sk_socket, reading l2cap_pi(sk)->chan in l2cap_sock_cleanup_listen() can race against concurrent l2cap_sock_kill() calls that nullify this pointer. This unsafe lockless read can cause a null pointer dereference. The fix involves taking the lock_sock() lock in l2cap_sock_kill() to synchronize with l2cap_sock_cleanup_listen(), eliminating the race and preventing the null pointer dereference.
Potential Impact
The vulnerability can cause a null pointer dereference in the Linux kernel Bluetooth stack, potentially leading to denial of service or kernel crashes. The CVSS score of 8.0 indicates high severity with impact on confidentiality, integrity, and availability. No known exploits in the wild have been reported.
Mitigation Recommendations
A fix is available that resolves the race condition by adding proper locking in the kernel Bluetooth L2CAP code. Users should apply the official Linux kernel updates that include this patch to remediate the vulnerability. Since this is a kernel-level issue, updating to a patched kernel version is the recommended mitigation.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-xgwm-wpg9-2232
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-90091"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6aade52755bf5e2cf5edc1c1
Added to database: 09/19/2026, 01:28:07 UTC
Last enriched: 09/19/2026, 01:54:16 UTC
Last updated: 09/19/2026, 02:21:28 UTC
Views: 2
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