{"id":"AZL-102777","summary":"CVE-2026-90091 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: fix race l2cap_sock_cleanup_listen() vs. put_chan\n\nFor L2CAP sockets without owning sk-\u003esk_socket, reading\nl2cap_pi(sk)-\u003echan may race against concurrent l2cap_sock_kill() -\u003e\nl2cap_sock_put_chan().  This excludes simultaneous proto_ops callbacks,\nbut access in l2cap_sock_cleanup_listen() has unsafe lockless read.\n\n [Task 1]                         [Task 2 (hdev-\u003eworkqueue)]\n l2cap_sock_release(parent)       l2cap_disconn_cfm\n   l2cap_sock_cleanup_listen        l2cap_conn_del\n     bt_accept_dequeue                l2cap_chan_del\n       lock_sock(sk)                    l2cap_sock_teardown_cb\n       bt_accept_unlink\n         bt_sk(sk)-\u003eparent = NULL\n       release_sock(sk) ----------------\u003e lock_sock(sk)\n                                          parent = /* NULL */\n     lock_sock(sk) \u003c--------------------- release_sock(sk)\n                                          sock_set_flag(sk, SOCK_ZAPPED)\n                                      l2cap_sock_close_cb\n                                        l2cap_sock_kill(sk)\n                                          l2cap_sock_put_chan\n     chan = READ l2cap_pi(sk)-\u003echan         l2cap_pi(sk)-\u003echan = NULL\n     l2cap_chan_hold_unless_zero            l2cap_put_chan(chan)\n       kref_get_unless_zero(&chan-\u003eref)\n\nTask 1 may observe NULL which causes null-ptr-deref.\n\nFix the race by taking lock_sock() in l2cap_sock_kill() to\nsynchronize with l2cap_sock_cleanup_listen().  hold_unless_zero() is not\nneeded here, l2cap_pi(sk)-\u003echan owns reference if it is non-NULL.\n\nClarify code comments vs. locking.","modified":"2026-09-18T14:16:35.007445022Z","published":"2026-09-17T17:17:00Z","upstream":["CVE-2026-90091"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90091"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-102777.json"}}],"schema_version":"1.9.0"}