CVE-2023-54203
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix slab-out-of-bounds in init_smb2_rsp_hdr
When smb1 mount fails, KASAN detect slab-out-of-bounds in init_smb2_rsp_hdr like the following one. For smb1 negotiate(56bytes) , init_smb2_rsp_hdr() for smb2 is called. The issue occurs while handling smb1 negotiate as smb2 server operations. Add smb server operations for smb1 (get_cmd_val, init_rsp_hdr, allocate_rsp_buf, check_user_session) to handle smb1 negotiate so that smb2 server operation does not handle it.
Detalles técnicos trazas, registros y código del informe original
[ 411.400423] CIFS: VFS: Use of the less secure dialect vers=1.0 is not recommended unless required for access to very old servers [ 411.400452] CIFS: Attempting to mount \\192.168.45.139\homes [ 411.479312] ksmbd: init_smb2_rsp_hdr : 492 [ 411.479323] ================================================================== [ 411.479327] BUG: KASAN: slab-out-of-bounds in init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd] [ 411.479369] Read of size 16 at addr ffff888488ed0734 by task kworker/14:1/199 [ 411.479379] CPU: 14 PID: 199 Comm: kworker/14:1 Tainted: G OE 6.1.21 #3 [ 411.479386] Hardware name: ASUSTeK COMPUTER INC. Z10PA-D8 Series/Z10PA-D8 Series, BIOS 3801 08/23/2019 [ 411.479390] Workqueue: ksmbd-io handle_ksmbd_work [ksmbd] [ 411.479425] Call Trace: [ 411.479428] <TASK> [ 411.479432] dump_stack_lvl+0x49/0x63 [ 411.479444] print_report+0x171/0x4a8 [ 411.479452] ? kasan_complete_mode_report_info+0x3c/0x200 [ 411.479463] ? init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd] [ 411.479497] kasan_report+0xb4/0x130 [ 411.479503] ? init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd] [ 411.479537] kasan_check_range+0x149/0x1e0 [ 411.479543] memcpy+0x24/0x70 [ 411.479550] init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd] [ 411.479585] handle_ksmbd_work+0x109/0x760 [ksmbd] [ 411.479616] ? _raw_spin_unlock_irqrestore+0x50/0x50 [ 411.479624] ? smb3_encrypt_resp+0x340/0x340 [ksmbd] [ 411.479656] process_one_work+0x49c/0x790 [ 411.479667] worker_thread+0x2b1/0x6e0 [ 411.479674] ? process_one_work+0x790/0x790 [ 411.479680] kthread+0x177/0x1b0 [ 411.479686] ? kthread_complete_and_exit+0x30/0x30 [ 411.479692] ret_from_fork+0x22/0x30 [ 411.479702] </TASK>
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- Puntuación base: 9.1
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.55%
- Percentil entre todas las CVEs puntuadas: 44
- 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
T1190Exploit Public-Facing Applicationinitial access75 % - Impacto principal
T1499.004Application or System Exploitationimpact85 % - Impacto secundario
T1005Data from Local Systemcollection60 %
Vulnerabilidad remota de negociación SMB (AV:N, PR:N, UI:N) en ksmbd que causa lectura fuera de límites (slab-out-of-bounds), permitiendo DoS por lectura de memoria no autorizada desde red sin autenticación.
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)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
JSON original (NVD)
Mostrar
{
"id": "CVE-2023-54203",
"cveTags": [],
"metrics": {
"cvssMetricV31": [
{
"type": "Secondary",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 9.1,
"attackVector": "NETWORK",
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.2,
"exploitabilityScore": 3.9
}
]
},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "51a8534c0f35c0401e45f1055f914729cad98bf9",
"lessThan": "921536046bd165efeb07beef5630aff35cd6a489",
"versionType": "git"
},
{
"status": "affected",
"version": "0b3ec5671ac06829ccebdaeec05acedfec327f42",
"lessThan": "a8334a0c535d0f0b4d64926c8fe0922ed98f7d43",
"versionType": "git"
},
{
"status": "affected",
"version": "cc32cd98a0aee4cc3eb611cbce11795b1aaa738a",
"lessThan": "99a51c673b1d2d0b5a972353401b77612d9cc713",
"versionType": "git"
},
{
"status": "affected",
"version": "39b291b86b5988bf8753c3874d5c773399d09b96",
"lessThan": "dc8289f912387c3bcfbc5d2db29c8947fa207c11",
"versionType": "git"
}
],
"programFiles": [
"fs/ksmbd/server.c",
"fs/ksmbd/smb2pdu.c",
"fs/ksmbd/smb_common.c",
"fs/ksmbd/smb_common.h"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.15.105",
"lessThan": "5.15.145",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.1.22",
"lessThan": "6.1.24",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.2.9",
"lessThan": "6.2.11",
"versionType": "semver"
}
],
"programFiles": [
"fs/ksmbd/server.c",
"fs/ksmbd/smb2pdu.c",
"fs/ksmbd/smb_common.c",
"fs/ksmbd/smb_common.h"
],
"defaultStatus": "unaffected"
}
]
}
],
"published": "2025-12-30T13:16:08.420",
"references": [
{
"url": "https://git.kernel.org/stable/c/921536046bd165efeb07beef5630aff35cd6a489",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/99a51c673b1d2d0b5a972353401b77612d9cc713",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/a8334a0c535d0f0b4d64926c8fe0922ed98f7d43",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/dc8289f912387c3bcfbc5d2db29c8947fa207c11",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Deferred",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix slab-out-of-bounds in init_smb2_rsp_hdr\n\nWhen smb1 mount fails, KASAN detect slab-out-of-bounds in\ninit_smb2_rsp_hdr like the following one.\nFor smb1 negotiate(56bytes) , init_smb2_rsp_hdr() for smb2 is called.\nThe issue occurs while handling smb1 negotiate as smb2 server operations.\nAdd smb server operations for smb1 (get_cmd_val, init_rsp_hdr,\nallocate_rsp_buf, check_user_session) to handle smb1 negotiate so that\nsmb2 server operation does not handle it.\n\n[ 411.400423] CIFS: VFS: Use of the less secure dialect vers=1.0 is\nnot recommended unless required for access to very old servers\n[ 411.400452] CIFS: Attempting to mount \\\\192.168.45.139\\homes\n[ 411.479312] ksmbd: init_smb2_rsp_hdr : 492\n[ 411.479323] ==================================================================\n[ 411.479327] BUG: KASAN: slab-out-of-bounds in\ninit_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd]\n[ 411.479369] Read of size 16 at addr ffff888488ed0734 by task kworker/14:1/199\n\n[ 411.479379] CPU: 14 PID: 199 Comm: kworker/14:1 Tainted: G\n OE 6.1.21 #3\n[ 411.479386] Hardware name: ASUSTeK COMPUTER INC. Z10PA-D8\nSeries/Z10PA-D8 Series, BIOS 3801 08/23/2019\n[ 411.479390] Workqueue: ksmbd-io handle_ksmbd_work [ksmbd]\n[ 411.479425] Call Trace:\n[ 411.479428] <TASK>\n[ 411.479432] dump_stack_lvl+0x49/0x63\n[ 411.479444] print_report+0x171/0x4a8\n[ 411.479452] ? kasan_complete_mode_report_info+0x3c/0x200\n[ 411.479463] ? init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd]\n[ 411.479497] kasan_report+0xb4/0x130\n[ 411.479503] ? init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd]\n[ 411.479537] kasan_check_range+0x149/0x1e0\n[ 411.479543] memcpy+0x24/0x70\n[ 411.479550] init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd]\n[ 411.479585] handle_ksmbd_work+0x109/0x760 [ksmbd]\n[ 411.479616] ? _raw_spin_unlock_irqrestore+0x50/0x50\n[ 411.479624] ? smb3_encrypt_resp+0x340/0x340 [ksmbd]\n[ 411.479656] process_one_work+0x49c/0x790\n[ 411.479667] worker_thread+0x2b1/0x6e0\n[ 411.479674] ? process_one_work+0x790/0x790\n[ 411.479680] kthread+0x177/0x1b0\n[ 411.479686] ? kthread_complete_and_exit+0x30/0x30\n[ 411.479692] ret_from_fork+0x22/0x30\n[ 411.479702] </TASK>"
}
],
"lastModified": "2026-08-04T11:16:36.580",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}