Vulnerability in Linux

[ Description ]Official description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: avoid socket lock inversion in listener cleanup rfcomm_sock_cleanup_listen() closes unaccepted child sockets through rfcomm_sock_close(), which takes the child socket lock before rfcomm_dlc_close() acquires rfcomm_mutex. The RFCOMM worker takes these locks in reverse order while handling connections and DLC state changes, so lockdep reports a possible deadlock. Close dequeued children without taking their socket lock. The accept queue owns a reference to each child, and bt_accept_dequeue() locks the child while unlinking it and clearing its parent pointer. Dropping the child lock makes it important to prevent a concurrent rfcomm_connect_ind() from enqueueing a new child after cleanup observes an empty queue. Set a listening socket to BT_CLOSED while its lock is still held, before dropping the lock and draining the queue. The state check in rfcomm_connect_ind() then rejects new children once cleanup starts.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund5 Oct 2026WID-SEC-2026-3743

  Linux Kernel: Multiple vulnerabilities Translated from German

  Risk mediumCVE-2026-98221CVE-2026-98181CVE-2026-98248+204 more CVEs

[ References ]References

• git.kernel.org/stable/c/18174b166547ef41973cc19feb5ef9cab39a8def
• git.kernel.org/stable/c/4aafb47301a799d3e01230d6568c4e93524e1523
• git.kernel.org/stable/c/801fb950cae7048eb7d83b18857d1ca37b8cd5a4
• git.kernel.org/stable/c/bfce253f039eb5f58b810af267942a9f59207254
• git.kernel.org/stable/c/c6792c441767256030606eb82dca5d5fc360dd9a
• git.kernel.org/stable/c/c741977e413f5b49d306700820fb55ccb8269f5a
• git.kernel.org/stable/c/eb4adaa46e4c9e6efa7be3ce06398f4d7c39b57c