CVE-2026-68117

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> tipc: clear sock-&gt;sk on the failed-insert path in tipc_sk_create()<br /> <br /> When tipc_sk_create() fails to insert the new socket (tipc_sk_insert()<br /> returns non-zero), its error path frees the sk with sk_free() but leaves<br /> sock-&gt;sk pointing at the freed object:<br /> <br /> if (tipc_sk_insert(tsk)) {<br /> sk_free(sk);<br /> pr_warn("Socket create failed; port number exhausted\n");<br /> return -EINVAL;<br /> }<br /> <br /> This is harmless for plain socket(): the syscall layer clears sock-&gt;ops<br /> before releasing, so tipc_release() is never called. It is not harmless<br /> on the accept() path. tipc_accept() creates the pre-allocated child<br /> socket with tipc_sk_create(net, new_sock, 0, kern); on failure it leaves<br /> new_sock-&gt;sk dangling and new_sock-&gt;ops non-NULL, and do_accept() then<br /> fput()s the new file, so __sock_release() -&gt; tipc_release() runs<br /> lock_sock(new_sock-&gt;sk) on the freed sk -- a use-after-free write of the<br /> sk_lock spinlock.<br /> <br /> tipc_release() already guards this exact "failed accept() releases a<br /> pre-allocated child" case with "if (sk == NULL) return 0;", but the<br /> guard is bypassed because tipc_sk_create() left sock-&gt;sk non-NULL<br /> (dangling) rather than NULL.<br /> <br /> Clear sock-&gt;sk on the failed-insert path so the existing tipc_release()<br /> NULL check fires and the use-after-free is avoided.<br /> <br /> The tipc_sk_insert() failure is reached when the per-netns socket<br /> rhashtable hits its max_size (tsk_rht_params.max_size = 1048576, ~2M<br /> elements) -- i.e. once a netns holds ~2M TIPC sockets every insert<br /> returns -E2BIG.<br /> <br /> BUG: KASAN: slab-use-after-free in lock_sock_nested (net/core/sock.c:3839)<br /> Write of size 8 at addr ffff8880047cdc38 by task init/1<br /> lock_sock_nested (net/core/sock.c:3839)<br /> tipc_release (net/tipc/socket.c:638)<br /> __sock_release (net/socket.c:710)<br /> sock_close (net/socket.c:1501)<br /> __fput (fs/file_table.c:512)<br /> Allocated by task 1:<br /> sk_alloc (net/core/sock.c:2308)<br /> tipc_sk_create (net/tipc/socket.c:487)<br /> tipc_accept (net/tipc/socket.c:2744)<br /> do_accept (net/socket.c:2034)<br /> Freed by task 1:<br /> __sk_destruct (net/core/sock.c:2391)<br /> tipc_sk_create (net/tipc/socket.c:504)<br /> tipc_accept (net/tipc/socket.c:2744)<br /> do_accept (net/socket.c:2034)