GHSA-6JH6-F787-4G5P
Vulnerability from github – Published: 2025-10-07 18:31 – Updated: 2026-02-05 15:31In the Linux kernel, the following vulnerability has been resolved:
tipc: fix a null-ptr-deref in tipc_topsrv_accept
syzbot found a crash in tipc_topsrv_accept:
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] Workqueue: tipc_rcv tipc_topsrv_accept RIP: 0010:kernel_accept+0x22d/0x350 net/socket.c:3487 Call Trace: tipc_topsrv_accept+0x197/0x280 net/tipc/topsrv.c:460 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
It was caused by srv->listener that might be set to null by tipc_topsrv_stop() in net .exit whereas it's still used in tipc_topsrv_accept() worker.
srv->listener is protected by srv->idr_lock in tipc_topsrv_stop(), so add a check for srv->listener under srv->idr_lock in tipc_topsrv_accept() to avoid the null-ptr-deref. To ensure the lsock is not released during the tipc_topsrv_accept(), move sock_release() after tipc_topsrv_work_stop() where it's waiting until the tipc_topsrv_accept worker to be done.
Note that sk_callback_lock is used to protect sk->sk_user_data instead of srv->listener, and it should check srv in tipc_topsrv_listener_data_ready() instead. This also ensures that no more tipc_topsrv_accept worker will be started after tipc_conn_close() is called in tipc_topsrv_stop() where it sets sk->sk_user_data to null.
{
"affected": [],
"aliases": [
"CVE-2022-50555"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-10-07T16:15:43Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: fix a null-ptr-deref in tipc_topsrv_accept\n\nsyzbot found a crash in tipc_topsrv_accept:\n\n KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]\n Workqueue: tipc_rcv tipc_topsrv_accept\n RIP: 0010:kernel_accept+0x22d/0x350 net/socket.c:3487\n Call Trace:\n \u003cTASK\u003e\n tipc_topsrv_accept+0x197/0x280 net/tipc/topsrv.c:460\n process_one_work+0x991/0x1610 kernel/workqueue.c:2289\n worker_thread+0x665/0x1080 kernel/workqueue.c:2436\n kthread+0x2e4/0x3a0 kernel/kthread.c:376\n ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306\n\nIt was caused by srv-\u003elistener that might be set to null by\ntipc_topsrv_stop() in net .exit whereas it\u0027s still used in\ntipc_topsrv_accept() worker.\n\nsrv-\u003elistener is protected by srv-\u003eidr_lock in tipc_topsrv_stop(), so add\na check for srv-\u003elistener under srv-\u003eidr_lock in tipc_topsrv_accept() to\navoid the null-ptr-deref. To ensure the lsock is not released during the\ntipc_topsrv_accept(), move sock_release() after tipc_topsrv_work_stop()\nwhere it\u0027s waiting until the tipc_topsrv_accept worker to be done.\n\nNote that sk_callback_lock is used to protect sk-\u003esk_user_data instead of\nsrv-\u003elistener, and it should check srv in tipc_topsrv_listener_data_ready()\ninstead. This also ensures that no more tipc_topsrv_accept worker will be\nstarted after tipc_conn_close() is called in tipc_topsrv_stop() where it\nsets sk-\u003esk_user_data to null.",
"id": "GHSA-6jh6-f787-4g5p",
"modified": "2026-02-05T15:31:08Z",
"published": "2025-10-07T18:31:09Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-50555"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/24b129aed8730e48f47d852d58d76825ab6f407c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/32a3d4660b34ce49ac0162338ebe362098e2f5df"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7a939503fc32bff4ed60800b73ff7fbb4aea2142"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/82cb4e4612c633a9ce320e1773114875604a3cce"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ce69bdac2310152bb70845024d5d704c52aabfc3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cedb41664e27b2cae7e21487f1bee22dcd84037d"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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