CVE-2025-38734
Estado: ModificadaAlta (7.8)—
In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix UAF on smcsk after smc_listen_out()
BPF CI testing report a UAF issue:
The direct cause of this issue is that after smc_listen_out_connected(), newclcsock->sk may be NULL since it will releases the smcsk. Therefore, if the application closes the socket immediately after accept, newclcsock->sk can be NULL. A possible execution order could be as follows:
smc_listen_work | userspace ----------------------------------------------------------------- lock_sock(sk) | smc_listen_out_connected() | | \- smc_listen_out | | | \- release_sock | | |- sk->sk_data_ready() | | fd = accept(); | close(fd); | \- socket->sk = NULL; /* newclcsock->sk is NULL now */ SMC_STAT_SERV_SUCC_INC(sock_net(newclcsock->sk))
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Since smc_listen_out_connected() will not fail, simply swapping the order of the code can easily fix this issue.
Detalles técnicos trazas, registros y código del informe original
[ 16.446633] BUG: kernel NULL pointer dereference, address: 000000000000003 0 [ 16.447134] #PF: supervisor read access in kernel mod e [ 16.447516] #PF: error_code(0x0000) - not-present pag e [ 16.447878] PGD 0 P4D 0 [ 16.448063] Oops: Oops: 0000 [#1] PREEMPT SMP NOPT I [ 16.448409] CPU: 0 UID: 0 PID: 9 Comm: kworker/0:1 Tainted: G OE 6.13.0-rc3-g89e8a75fda73-dirty #4 2 [ 16.449124] Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODUL E [ 16.449502] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/201 4 [ 16.450201] Workqueue: smc_hs_wq smc_listen_wor k [ 16.450531] RIP: 0010:smc_listen_work+0xc02/0x159 0 [ 16.452158] RSP: 0018:ffffb5ab40053d98 EFLAGS: 0001024 6 [ 16.452526] RAX: 0000000000000001 RBX: 0000000000000002 RCX: 000000000000030 0 [ 16.452994] RDX: 0000000000000280 RSI: 00003513840053f0 RDI: 000000000000000 0 [ 16.453492] RBP: ffffa097808e3800 R08: ffffa09782dba1e0 R09: 000000000000000 5 [ 16.453987] R10: 0000000000000000 R11: 0000000000000000 R12: ffffa0978274640 0 [ 16.454497] R13: 0000000000000000 R14: 0000000000000000 R15: ffffa09782d4092 0 [ 16.454996] FS: 0000000000000000(0000) GS:ffffa097bbc00000(0000) knlGS:000000000000000 0 [ 16.455557] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003 3 [ 16.455961] CR2: 0000000000000030 CR3: 0000000102788004 CR4: 0000000000770ef 0 [ 16.456459] PKRU: 5555555 4 [ 16.456654] Call Trace : [ 16.456832] <TASK > [ 16.456989] ? __die+0x23/0x7 0 [ 16.457215] ? page_fault_oops+0x180/0x4c 0 [ 16.457508] ? __lock_acquire+0x3e6/0x249 0 [ 16.457801] ? exc_page_fault+0x68/0x20 0 [ 16.458080] ? asm_exc_page_fault+0x26/0x3 0 [ 16.458389] ? smc_listen_work+0xc02/0x159 0 [ 16.458689] ? smc_listen_work+0xc02/0x159 0 [ 16.458987] ? lock_is_held_type+0x8f/0x10 0 [ 16.459284] process_one_work+0x1ea/0x6d 0 [ 16.459570] worker_thread+0x1c3/0x38 0 [ 16.459839] ? __pfx_worker_thread+0x10/0x1 0 [ 16.460144] kthread+0xe0/0x11 0 [ 16.460372] ? __pfx_kthread+0x10/0x1 0 [ 16.460640] ret_from_fork+0x31/0x5 0 [ 16.460896] ? __pfx_kthread+0x10/0x1 0 [ 16.461166] ret_from_fork_asm+0x1a/0x3 0 [ 16.461453] </TASK > [ 16.461616] Modules linked in: bpf_testmod(OE) [last unloaded: bpf_testmod(OE) ] [ 16.462134] CR2: 000000000000003 0 [ 16.462380] ---[ end trace 0000000000000000 ]--- [ 16.462710] RIP: 0010:smc_listen_work+0xc02/0x1590
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Puntuación base: 7.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.46%
- Percentil entre todas las CVEs puntuadas: 38
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1068Exploitation for Privilege Escalationprivilege escalation75 % - Impacto principal
T1499.004Application or System Exploitationimpact70 %
UAF en kernel Linux (CWE-416) con AV:L/PR:L permite DoS por null pointer dereference en smc_listen_work tras smc_listen_out() liberar socket. No hay ejecución de código confirmada, solo crash del servicio.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
CWE
- CWE-416
Referencias
JSON original (NVD)
Mostrar
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"description": [
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix UAF on smcsk after smc_listen_out()\n\nBPF CI testing report a UAF issue:\n\n [ 16.446633] BUG: kernel NULL pointer dereference, address: 000000000000003 0\n [ 16.447134] #PF: supervisor read access in kernel mod e\n [ 16.447516] #PF: error_code(0x0000) - not-present pag e\n [ 16.447878] PGD 0 P4D 0\n [ 16.448063] Oops: Oops: 0000 [#1] PREEMPT SMP NOPT I\n [ 16.448409] CPU: 0 UID: 0 PID: 9 Comm: kworker/0:1 Tainted: G OE 6.13.0-rc3-g89e8a75fda73-dirty #4 2\n [ 16.449124] Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODUL E\n [ 16.449502] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/201 4\n [ 16.450201] Workqueue: smc_hs_wq smc_listen_wor k\n [ 16.450531] RIP: 0010:smc_listen_work+0xc02/0x159 0\n [ 16.452158] RSP: 0018:ffffb5ab40053d98 EFLAGS: 0001024 6\n [ 16.452526] RAX: 0000000000000001 RBX: 0000000000000002 RCX: 000000000000030 0\n [ 16.452994] RDX: 0000000000000280 RSI: 00003513840053f0 RDI: 000000000000000 0\n [ 16.453492] RBP: ffffa097808e3800 R08: ffffa09782dba1e0 R09: 000000000000000 5\n [ 16.453987] R10: 0000000000000000 R11: 0000000000000000 R12: ffffa0978274640 0\n [ 16.454497] R13: 0000000000000000 R14: 0000000000000000 R15: ffffa09782d4092 0\n [ 16.454996] FS: 0000000000000000(0000) GS:ffffa097bbc00000(0000) knlGS:000000000000000 0\n [ 16.455557] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003 3\n [ 16.455961] CR2: 0000000000000030 CR3: 0000000102788004 CR4: 0000000000770ef 0\n [ 16.456459] PKRU: 5555555 4\n [ 16.456654] Call Trace :\n [ 16.456832] <TASK >\n [ 16.456989] ? __die+0x23/0x7 0\n [ 16.457215] ? page_fault_oops+0x180/0x4c 0\n [ 16.457508] ? __lock_acquire+0x3e6/0x249 0\n [ 16.457801] ? exc_page_fault+0x68/0x20 0\n [ 16.458080] ? asm_exc_page_fault+0x26/0x3 0\n [ 16.458389] ? smc_listen_work+0xc02/0x159 0\n [ 16.458689] ? smc_listen_work+0xc02/0x159 0\n [ 16.458987] ? lock_is_held_type+0x8f/0x10 0\n [ 16.459284] process_one_work+0x1ea/0x6d 0\n [ 16.459570] worker_thread+0x1c3/0x38 0\n [ 16.459839] ? __pfx_worker_thread+0x10/0x1 0\n [ 16.460144] kthread+0xe0/0x11 0\n [ 16.460372] ? __pfx_kthread+0x10/0x1 0\n [ 16.460640] ret_from_fork+0x31/0x5 0\n [ 16.460896] ? __pfx_kthread+0x10/0x1 0\n [ 16.461166] ret_from_fork_asm+0x1a/0x3 0\n [ 16.461453] </TASK >\n [ 16.461616] Modules linked in: bpf_testmod(OE) [last unloaded: bpf_testmod(OE) ]\n [ 16.462134] CR2: 000000000000003 0\n [ 16.462380] ---[ end trace 0000000000000000 ]---\n [ 16.462710] RIP: 0010:smc_listen_work+0xc02/0x1590\n\nThe direct cause of this issue is that after smc_listen_out_connected(),\nnewclcsock->sk may be NULL since it will releases the smcsk. Therefore,\nif the application closes the socket immediately after accept,\nnewclcsock->sk can be NULL. A possible execution order could be as\nfollows:\n\nsmc_listen_work | userspace\n-----------------------------------------------------------------\nlock_sock(sk) |\nsmc_listen_out_connected() |\n| \\- smc_listen_out |\n| | \\- release_sock |\n | |- sk->sk_data_ready() |\n | fd = accept();\n | close(fd);\n | \\- socket->sk = NULL;\n/* newclcsock->sk is NULL now */\nSMC_STAT_SERV_SUCC_INC(sock_net(newclcsock->sk))\n\nSince smc_listen_out_connected() will not fail, simply swapping the order\nof the code can easily fix this issue."
}
],
"lastModified": "2026-07-30T06:23:38.660",
"configurations": [
{
"nodes": [
{
"negate": false,
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