CVE-2023-53500

Estado: ModificadaAlta (7.8)—

In the Linux kernel, the following vulnerability has been resolved:

xfrm: fix slab-use-after-free in decode_session6

When the xfrm device is set to the qdisc of the sfb type, the cb field of the sent skb may be modified during enqueuing. Then, slab-use-after-free may occur when the xfrm device sends IPv6 packets.

As commit f855691975bb ("xfrm6: Fix the nexthdr offset in _decode_session6.") showed, xfrm_decode_session was originally intended only for the receive path. IP6CB(skb)->nhoff is not set during transmission. Therefore, set the cb field in the skb to 0 before sending packets.

Detalles técnicos trazas, registros y código del informe original

The stack information is as follows:
BUG: KASAN: slab-use-after-free in decode_session6+0x103f/0x1890
Read of size 1 at addr ffff8881111458ef by task swapper/3/0
CPU: 3 PID: 0 Comm: swapper/3 Not tainted 6.4.0-next-20230707 #409
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl+0xd9/0x150
print_address_description.constprop.0+0x2c/0x3c0
kasan_report+0x11d/0x130
decode_session6+0x103f/0x1890
__xfrm_decode_session+0x54/0xb0
xfrmi_xmit+0x173/0x1ca0
dev_hard_start_xmit+0x187/0x700
sch_direct_xmit+0x1a3/0xc30
__qdisc_run+0x510/0x17a0
__dev_queue_xmit+0x2215/0x3b10
neigh_connected_output+0x3c2/0x550
ip6_finish_output2+0x55a/0x1550
ip6_finish_output+0x6b9/0x1270
ip6_output+0x1f1/0x540
ndisc_send_skb+0xa63/0x1890
ndisc_send_rs+0x132/0x6f0
addrconf_rs_timer+0x3f1/0x870
call_timer_fn+0x1a0/0x580
expire_timers+0x29b/0x4b0
run_timer_softirq+0x326/0x910
__do_softirq+0x1d4/0x905
irq_exit_rcu+0xb7/0x120
sysvec_apic_timer_interrupt+0x97/0xc0
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:intel_idle_hlt+0x23/0x30
Code: 1f 84 00 00 00 00 00 f3 0f 1e fa 41 54 41 89 d4 0f 1f 44 00 00 66 90 0f 1f 44 00 00 0f 00 2d c4 9f ab 00 0f 1f 44 00 00 fb f4 <fa> 44 89 e0 41 5c c3 66 0f 1f 44 00 00 f3 0f 1e fa 41 54 41 89 d4
RSP: 0018:ffffc90000197d78 EFLAGS: 00000246
RAX: 00000000000a83c3 RBX: ffffe8ffffd09c50 RCX: ffffffff8a22d8e5
RDX: 0000000000000001 RSI: ffffffff8d3f8080 RDI: ffffe8ffffd09c50
RBP: ffffffff8d3f8080 R08: 0000000000000001 R09: ffffed1026ba6d9d
R10: ffff888135d36ceb R11: 0000000000000001 R12: 0000000000000001
R13: ffffffff8d3f8100 R14: 0000000000000001 R15: 0000000000000000
cpuidle_enter_state+0xd3/0x6f0
cpuidle_enter+0x4e/0xa0
do_idle+0x2fe/0x3c0
cpu_startup_entry+0x18/0x20
start_secondary+0x200/0x290
secondary_startup_64_no_verify+0x167/0x16b
</TASK>
Allocated by task 939:
kasan_save_stack+0x22/0x40
kasan_set_track+0x25/0x30
__kasan_slab_alloc+0x7f/0x90
kmem_cache_alloc_node+0x1cd/0x410
kmalloc_reserve+0x165/0x270
__alloc_skb+0x129/0x330
inet6_ifa_notify+0x118/0x230
__ipv6_ifa_notify+0x177/0xbe0
addrconf_dad_completed+0x133/0xe00
addrconf_dad_work+0x764/0x1390
process_one_work+0xa32/0x16f0
worker_thread+0x67d/0x10c0
kthread+0x344/0x440
ret_from_fork+0x1f/0x30
The buggy address belongs to the object at ffff888111145800
which belongs to the cache skbuff_small_head of size 640
The buggy address is located 239 bytes inside of
freed 640-byte region [ffff888111145800, ffff888111145a80)

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: 0.16%
Percentil entre todas las CVEs puntuadas: 5
Fecha de la puntuación: 6/10/2026

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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1499.004 Application or System Exploitationimpact75 %
Impacto secundarioT1529 System Shutdown/Rebootimpact65 %

CVE-2023-53500 es una slab-use-after-free en el kernel Linux (CWE-416) con acceso local (AV:L) y privilegios limitados (PR:L), explotable sin interacción; causa DoS por lectura de memoria corrupta y potencial crash de kernel.

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

Threat Intelligence Program Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-416

Referencias

JSON original (NVD)

Mostrar

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      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: fix slab-use-after-free in decode_session6\n\nWhen the xfrm device is set to the qdisc of the sfb type, the cb field\nof the sent skb may be modified during enqueuing. Then,\nslab-use-after-free may occur when the xfrm device sends IPv6 packets.\n\nThe stack information is as follows:\nBUG: KASAN: slab-use-after-free in decode_session6+0x103f/0x1890\nRead of size 1 at addr ffff8881111458ef by task swapper/3/0\nCPU: 3 PID: 0 Comm: swapper/3 Not tainted 6.4.0-next-20230707 #409\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014\nCall Trace:\n<IRQ>\ndump_stack_lvl+0xd9/0x150\nprint_address_description.constprop.0+0x2c/0x3c0\nkasan_report+0x11d/0x130\ndecode_session6+0x103f/0x1890\n__xfrm_decode_session+0x54/0xb0\nxfrmi_xmit+0x173/0x1ca0\ndev_hard_start_xmit+0x187/0x700\nsch_direct_xmit+0x1a3/0xc30\n__qdisc_run+0x510/0x17a0\n__dev_queue_xmit+0x2215/0x3b10\nneigh_connected_output+0x3c2/0x550\nip6_finish_output2+0x55a/0x1550\nip6_finish_output+0x6b9/0x1270\nip6_output+0x1f1/0x540\nndisc_send_skb+0xa63/0x1890\nndisc_send_rs+0x132/0x6f0\naddrconf_rs_timer+0x3f1/0x870\ncall_timer_fn+0x1a0/0x580\nexpire_timers+0x29b/0x4b0\nrun_timer_softirq+0x326/0x910\n__do_softirq+0x1d4/0x905\nirq_exit_rcu+0xb7/0x120\nsysvec_apic_timer_interrupt+0x97/0xc0\n</IRQ>\n<TASK>\nasm_sysvec_apic_timer_interrupt+0x1a/0x20\nRIP: 0010:intel_idle_hlt+0x23/0x30\nCode: 1f 84 00 00 00 00 00 f3 0f 1e fa 41 54 41 89 d4 0f 1f 44 00 00 66 90 0f 1f 44 00 00 0f 00 2d c4 9f ab 00 0f 1f 44 00 00 fb f4 <fa> 44 89 e0 41 5c c3 66 0f 1f 44 00 00 f3 0f 1e fa 41 54 41 89 d4\nRSP: 0018:ffffc90000197d78 EFLAGS: 00000246\nRAX: 00000000000a83c3 RBX: ffffe8ffffd09c50 RCX: ffffffff8a22d8e5\nRDX: 0000000000000001 RSI: ffffffff8d3f8080 RDI: ffffe8ffffd09c50\nRBP: ffffffff8d3f8080 R08: 0000000000000001 R09: ffffed1026ba6d9d\nR10: ffff888135d36ceb R11: 0000000000000001 R12: 0000000000000001\nR13: ffffffff8d3f8100 R14: 0000000000000001 R15: 0000000000000000\ncpuidle_enter_state+0xd3/0x6f0\ncpuidle_enter+0x4e/0xa0\ndo_idle+0x2fe/0x3c0\ncpu_startup_entry+0x18/0x20\nstart_secondary+0x200/0x290\nsecondary_startup_64_no_verify+0x167/0x16b\n</TASK>\nAllocated by task 939:\nkasan_save_stack+0x22/0x40\nkasan_set_track+0x25/0x30\n__kasan_slab_alloc+0x7f/0x90\nkmem_cache_alloc_node+0x1cd/0x410\nkmalloc_reserve+0x165/0x270\n__alloc_skb+0x129/0x330\ninet6_ifa_notify+0x118/0x230\n__ipv6_ifa_notify+0x177/0xbe0\naddrconf_dad_completed+0x133/0xe00\naddrconf_dad_work+0x764/0x1390\nprocess_one_work+0xa32/0x16f0\nworker_thread+0x67d/0x10c0\nkthread+0x344/0x440\nret_from_fork+0x1f/0x30\nThe buggy address belongs to the object at ffff888111145800\nwhich belongs to the cache skbuff_small_head of size 640\nThe buggy address is located 239 bytes inside of\nfreed 640-byte region [ffff888111145800, ffff888111145a80)\n\nAs commit f855691975bb (\"xfrm6: Fix the nexthdr offset in\n_decode_session6.\") showed, xfrm_decode_session was originally intended\nonly for the receive path. IP6CB(skb)->nhoff is not set during\ntransmission. Therefore, set the cb field in the skb to 0 before\nsending packets."
    }
  ],
  "lastModified": "2026-08-04T10:19:09.653",
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}