CVE-2025-39852
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: net/tcp: Fix socket memory leak in TCP-AO failure handling for IPv6 When tcp_ao_copy_all_matching() fails in tcp_v6_syn_recv_sock() it just exits the function. This ends up causing a memory-leak: unreferenced object 0xffff0000281a8200 (size 2496): comm "softirq", pid 0, jiffies 4295174684 hex dump (first 32 bytes): 7f 00 00 06 7f 00 00 06 00 00 00 00 cb a8 88 13 ................ 0a 00 03 61 00 00 00 00 00 00 00 00 00 00 00 00 ...a............ backtrace (crc 5ebdbe15): kmemleak_alloc+0x44/0xe0 kmem_cache_alloc_noprof+0x248/0x470 sk_prot_alloc+0x48/0x120 sk_clone_lock+0x38/0x3b0 inet_csk_clone_lock+0x34/0x150 tcp_create_openreq_child+0x3c/0x4a8 tcp_v6_syn_recv_sock+0x1c0/0x620 tcp_check_req+0x588/0x790 tcp_v6_rcv+0x5d0/0xc18 ip6_protocol_deliver_rcu+0x2d8/0x4c0 ip6_input_finish+0x74/0x148 ip6_input+0x50/0x118 ip6_sublist_rcv+0x2fc/0x3b0 ipv6_list_rcv+0x114/0x170 __netif_receive_skb_list_core+0x16c/0x200 netif_receive_skb_list_internal+0x1f0/0x2d0 This is because in tcp_v6_syn_recv_sock (and the IPv4 counterpart), when exiting upon error, inet_csk_prepare_forced_close() and tcp_done() need to be called. They make sure the newsk will end up being correctly free'd. tcp_v4_syn_recv_sock() makes this very clear by having the put_and_exit label that takes care of things. So, this patch here makes sure tcp_v4_syn_recv_sock and tcp_v6_syn_recv_sock have similar error-handling and thus fixes the leak for TCP-AO.
Severity
MEDIUM
CVSS score
5.5
(v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-09-19 16:15:44.090000
Last modified
2026-10-19 21:10:00.160000
View original CVE JSON
{
"id": "CVE-2025-39852",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2025-09-19T16:15:44.090",
"lastModified": "2026-10-19T21:10:00.160",
"vulnStatus": "Modified",
"cveTags": [],
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{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp: Fix socket memory leak in TCP-AO failure handling for IPv6\n\nWhen tcp_ao_copy_all_matching() fails in tcp_v6_syn_recv_sock() it just\nexits the function. This ends up causing a memory-leak:\n\nunreferenced object 0xffff0000281a8200 (size 2496):\n comm \"softirq\", pid 0, jiffies 4295174684\n hex dump (first 32 bytes):\n 7f 00 00 06 7f 00 00 06 00 00 00 00 cb a8 88 13 ................\n 0a 00 03 61 00 00 00 00 00 00 00 00 00 00 00 00 ...a............\n backtrace (crc 5ebdbe15):\n kmemleak_alloc+0x44/0xe0\n kmem_cache_alloc_noprof+0x248/0x470\n sk_prot_alloc+0x48/0x120\n sk_clone_lock+0x38/0x3b0\n inet_csk_clone_lock+0x34/0x150\n tcp_create_openreq_child+0x3c/0x4a8\n tcp_v6_syn_recv_sock+0x1c0/0x620\n tcp_check_req+0x588/0x790\n tcp_v6_rcv+0x5d0/0xc18\n ip6_protocol_deliver_rcu+0x2d8/0x4c0\n ip6_input_finish+0x74/0x148\n ip6_input+0x50/0x118\n ip6_sublist_rcv+0x2fc/0x3b0\n ipv6_list_rcv+0x114/0x170\n __netif_receive_skb_list_core+0x16c/0x200\n netif_receive_skb_list_internal+0x1f0/0x2d0\n\nThis is because in tcp_v6_syn_recv_sock (and the IPv4 counterpart), when\nexiting upon error, inet_csk_prepare_forced_close() and tcp_done() need\nto be called. They make sure the newsk will end up being correctly\nfree'd.\n\ntcp_v4_syn_recv_sock() makes this very clear by having the put_and_exit\nlabel that takes care of things. So, this patch here makes sure\ntcp_v4_syn_recv_sock and tcp_v6_syn_recv_sock have similar\nerror-handling and thus fixes the leak for TCP-AO."
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet/tcp: Corrige la fuga de memoria del socket en el manejo de fallos de TCP-AO para IPv6\n\nCuando tcp_ao_copy_all_matching() falla en tcp_v6_syn_recv_sock(), simplemente sale de la función. Esto termina causando una fuga de memoria:\n\nobjeto sin referencia 0xffff0000281a8200 (tamaño 2496):\n comm 'softirq', pid 0, jiffies 4295174684\n volcado hexadecimal (primeros 32 bytes):\n 7f 00 00 06 7f 00 00 06 00 00 00 00 cb a8 88 13 ................\n 0a 00 03 61 00 00 00 00 00 00 00 00 00 00 00 00 ...a............\n backtrace (crc 5ebdbe15):\n kmemleak_alloc+0x44/0xe0\n kmem_cache_alloc_noprof+0x248/0x470\n sk_prot_alloc+0x48/0x120\n sk_clone_lock+0x38/0x3b0\n inet_csk_clone_lock+0x34/0x150\n tcp_create_openreq_child+0x3c/0x4a8\n tcp_v6_syn_recv_sock+0x1c0/0x620\n tcp_check_req+0x588/0x790\n tcp_v6_rcv+0x5d0/0xc18\n ip6_protocol_deliver_rcu+0x2d8/0x4c0\n ip6_input_finish+0x74/0x148\n ip6_input+0x50/0x118\n ip6_sublist_rcv+0x2fc/0x3b0\n ipv6_list_rcv+0x114/0x170\n __netif_receive_skb_list_core+0x16c/0x200\n netif_receive_skb_list_internal+0x1f0/0x2d0\n\nEsto se debe a que en tcp_v6_syn_recv_sock (y su contraparte IPv4), al salir por error, inet_csk_prepare_forced_close() y tcp_done() deben ser llamadas. Aseguran que el newsk terminará siendo liberado correctamente.\n\ntcp_v4_syn_recv_sock() lo deja muy claro al tener la etiqueta put_and_exit que se encarga de las cosas. Así, este parche asegura que tcp_v4_syn_recv_sock y tcp_v6_syn_recv_sock tengan un manejo de errores similar y, por lo tanto, corrige la fuga para TCP-AO."
}
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