{"cve":"CVE-2024-56642","nvd":{"published":"2024-12-27T15:15:23.930","modified":"2026-06-17T08:12:37.420","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: Fix use-after-free of kernel socket in cleanup_bearer().\n\nsyzkaller reported a use-after-free of UDP kernel socket\nin cleanup_bearer() without repro. [0][1]\n\nWhen bearer_disable() calls tipc_udp_disable(), cleanup\nof the UDP kernel socket is deferred by work calling\ncleanup_bearer().\n\ntipc_exit_net() waits for such works to finish by checking\ntipc_net(net)->wq_count.  However, the work decrements the\ncount too early before releasing the kernel socket,\nunblocking cleanup_net() and resulting in use-after-free.\n\nLet's move the decrement after releasing the socket in\ncleanup_bearer().\n\n[0]:\nref_tracker: net notrefcnt@000000009b3d1faf has 1/1 users at\n     sk_alloc+0x438/0x608\n     inet_create+0x4c8/0xcb0\n     __sock_create+0x350/0x6b8\n     sock_create_kern+0x58/0x78\n     udp_sock_create4+0x68/0x398\n     udp_sock_create+0x88/0xc8\n     tipc_udp_enable+0x5e8/0x848\n     __tipc_nl_bearer_enable+0x84c/0xed8\n     tipc_nl_bearer_enable+0x38/0x60\n     genl_family_rcv_msg_doit+0x170/0x248\n     genl_rcv_msg+0x400/0x5b0\n     netlink_rcv_skb+0x1dc/0x398\n     genl_rcv+0x44/0x68\n     netlink_unicast+0x678/0x8b0\n     netlink_sendmsg+0x5e4/0x898\n     ____sys_sendmsg+0x500/0x830\n\n[1]:\nBUG: KMSAN: use-after-free in udp_hashslot include/net/udp.h:85 [inline]\nBUG: KMSAN: use-after-free in udp_lib_unhash+0x3b8/0x930 net/ipv4/udp.c:1979\n udp_hashslot include/net/udp.h:85 [inline]\n udp_lib_unhash+0x3b8/0x930 net/ipv4/udp.c:1979\n sk_common_release+0xaf/0x3f0 net/core/sock.c:3820\n inet_release+0x1e0/0x260 net/ipv4/af_inet.c:437\n inet6_release+0x6f/0xd0 net/ipv6/af_inet6.c:489\n __sock_release net/socket.c:658 [inline]\n sock_release+0xa0/0x210 net/socket.c:686\n cleanup_bearer+0x42d/0x4c0 net/tipc/udp_media.c:819\n process_one_work kernel/workqueue.c:3229 [inline]\n process_scheduled_works+0xcaf/0x1c90 kernel/workqueue.c:3310\n worker_thread+0xf6c/0x1510 kernel/workqueue.c:3391\n kthread+0x531/0x6b0 kernel/kthread.c:389\n ret_from_fork+0x60/0x80 arch/x86/kernel/process.c:147\n ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244\n\nUninit was created at:\n slab_free_hook mm/slub.c:2269 [inline]\n slab_free mm/slub.c:4580 [inline]\n kmem_cache_free+0x207/0xc40 mm/slub.c:4682\n net_free net/core/net_namespace.c:454 [inline]\n cleanup_net+0x16f2/0x19d0 net/core/net_namespace.c:647\n process_one_work kernel/workqueue.c:3229 [inline]\n process_scheduled_works+0xcaf/0x1c90 kernel/workqueue.c:3310\n worker_thread+0xf6c/0x1510 kernel/workqueue.c:3391\n kthread+0x531/0x6b0 kernel/kthread.c:389\n ret_from_fork+0x60/0x80 arch/x86/kernel/process.c:147\n ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244\n\nCPU: 0 UID: 0 PID: 54 Comm: kworker/0:2 Not tainted 6.12.0-rc1-00131-gf66ebf37d69c #7 91723d6f74857f70725e1583cba3cf4adc716cfa\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\nWorkqueue: events cleanup_bearer","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/4e69457f9dfae67435f3ccf29008768eae860415","https://git.kernel.org/stable/c/650ee9a22d7a2de8999fac2d45983597a0c22359","https://git.kernel.org/stable/c/6a2fa13312e51a621f652d522d7e2df7066330b6","https://git.kernel.org/stable/c/d00d4470bf8c4282617a3a10e76b20a9c7e4cffa","https://git.kernel.org/stable/c/d2a4894f238551eae178904e7f45af87577074fd"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:57:56.913276502+00:00"},"epss":{"cve":"CVE-2024-56642","score":0.00243,"percentile":0.15601,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}