GHSA-QMXC-QV48-VP67
Vulnerability from github – Published: 2026-08-10 15:33 – Updated: 2026-08-19 18:32In the Linux kernel, the following vulnerability has been resolved:
tipc: clear sock->sk on the failed-insert path in tipc_sk_create()
When tipc_sk_create() fails to insert the new socket (tipc_sk_insert() returns non-zero), its error path frees the sk with sk_free() but leaves sock->sk pointing at the freed object:
if (tipc_sk_insert(tsk)) {
sk_free(sk);
pr_warn("Socket create failed; port number exhausted\n");
return -EINVAL;
}
This is harmless for plain socket(): the syscall layer clears sock->ops before releasing, so tipc_release() is never called. It is not harmless on the accept() path. tipc_accept() creates the pre-allocated child socket with tipc_sk_create(net, new_sock, 0, kern); on failure it leaves new_sock->sk dangling and new_sock->ops non-NULL, and do_accept() then fput()s the new file, so __sock_release() -> tipc_release() runs lock_sock(new_sock->sk) on the freed sk -- a use-after-free write of the sk_lock spinlock.
tipc_release() already guards this exact "failed accept() releases a pre-allocated child" case with "if (sk == NULL) return 0;", but the guard is bypassed because tipc_sk_create() left sock->sk non-NULL (dangling) rather than NULL.
Clear sock->sk on the failed-insert path so the existing tipc_release() NULL check fires and the use-after-free is avoided.
The tipc_sk_insert() failure is reached when the per-netns socket rhashtable hits its max_size (tsk_rht_params.max_size = 1048576, ~2M elements) -- i.e. once a netns holds ~2M TIPC sockets every insert returns -E2BIG.
BUG: KASAN: slab-use-after-free in lock_sock_nested (net/core/sock.c:3839) Write of size 8 at addr ffff8880047cdc38 by task init/1 lock_sock_nested (net/core/sock.c:3839) tipc_release (net/tipc/socket.c:638) __sock_release (net/socket.c:710) sock_close (net/socket.c:1501) __fput (fs/file_table.c:512) Allocated by task 1: sk_alloc (net/core/sock.c:2308) tipc_sk_create (net/tipc/socket.c:487) tipc_accept (net/tipc/socket.c:2744) do_accept (net/socket.c:2034) Freed by task 1: __sk_destruct (net/core/sock.c:2391) tipc_sk_create (net/tipc/socket.c:504) tipc_accept (net/tipc/socket.c:2744) do_accept (net/socket.c:2034)
{
"affected": [],
"aliases": [
"CVE-2026-68117"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-10T13:19:56Z",
"severity": "CRITICAL"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: clear sock-\u003esk on the failed-insert path in tipc_sk_create()\n\nWhen tipc_sk_create() fails to insert the new socket (tipc_sk_insert()\nreturns non-zero), its error path frees the sk with sk_free() but leaves\nsock-\u003esk pointing at the freed object:\n\n\tif (tipc_sk_insert(tsk)) {\n\t\tsk_free(sk);\n\t\tpr_warn(\"Socket create failed; port number exhausted\\n\");\n\t\treturn -EINVAL;\n\t}\n\nThis is harmless for plain socket(): the syscall layer clears sock-\u003eops\nbefore releasing, so tipc_release() is never called. It is not harmless\non the accept() path. tipc_accept() creates the pre-allocated child\nsocket with tipc_sk_create(net, new_sock, 0, kern); on failure it leaves\nnew_sock-\u003esk dangling and new_sock-\u003eops non-NULL, and do_accept() then\nfput()s the new file, so __sock_release() -\u003e tipc_release() runs\nlock_sock(new_sock-\u003esk) on the freed sk -- a use-after-free write of the\nsk_lock spinlock.\n\ntipc_release() already guards this exact \"failed accept() releases a\npre-allocated child\" case with \"if (sk == NULL) return 0;\", but the\nguard is bypassed because tipc_sk_create() left sock-\u003esk non-NULL\n(dangling) rather than NULL.\n\nClear sock-\u003esk on the failed-insert path so the existing tipc_release()\nNULL check fires and the use-after-free is avoided.\n\nThe tipc_sk_insert() failure is reached when the per-netns socket\nrhashtable hits its max_size (tsk_rht_params.max_size = 1048576, ~2M\nelements) -- i.e. once a netns holds ~2M TIPC sockets every insert\nreturns -E2BIG.\n\n BUG: KASAN: slab-use-after-free in lock_sock_nested (net/core/sock.c:3839)\n Write of size 8 at addr ffff8880047cdc38 by task init/1\n lock_sock_nested (net/core/sock.c:3839)\n tipc_release (net/tipc/socket.c:638)\n __sock_release (net/socket.c:710)\n sock_close (net/socket.c:1501)\n __fput (fs/file_table.c:512)\n Allocated by task 1:\n sk_alloc (net/core/sock.c:2308)\n tipc_sk_create (net/tipc/socket.c:487)\n tipc_accept (net/tipc/socket.c:2744)\n do_accept (net/socket.c:2034)\n Freed by task 1:\n __sk_destruct (net/core/sock.c:2391)\n tipc_sk_create (net/tipc/socket.c:504)\n tipc_accept (net/tipc/socket.c:2744)\n do_accept (net/socket.c:2034)",
"id": "GHSA-qmxc-qv48-vp67",
"modified": "2026-08-19T18:32:05Z",
"published": "2026-08-10T15:33:36Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68117"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5f5a41a48dbf9eda57b67ce23e548602cf7195a6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/82f59aa27f33bd014a7d8739371ab5712d15e33b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8d6f26d48e61ef34f1921289401dbf36b10816af"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b07d87b31631edb6529e6cdcca790a7489d1250d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ba0533fc163f905fe817cfabdf8ed4058da44800"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dd29891ed840f6b8d020b759d0dc4a00b1d6e4ea"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/efebc23e9b29e3e5a9e2127dd066929f7f0d315e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f9596b1566616a8be0592dbceccb6344a7c6f6bb"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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