CVE-2023-53846
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to do sanity check on direct node in truncate_dnode()
syzbot reports below bug:
The root cause is, inodeA references inodeB via inodeB's ino, once inodeA is truncated, it calls truncate_dnode() to truncate data blocks in inodeB's node page, it traverse mapping data from node->i.i_addr[0] to node->i.i_addr[ADDRS_PER_BLOCK() - 1], result in out-of-boundary access.
This patch fixes to add sanity check on dnode page in truncate_dnode(), so that, it can help to avoid triggering such issue, and once it encounters such issue, it will record newly introduced ERROR_INVALID_NODE_REFERENCE error into superblock, later fsck can detect such issue and try repairing.
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Also, it removes f2fs_truncate_data_blocks() for cleanup due to the function has only one caller, and uses f2fs_truncate_data_blocks_range() instead.
Detalles técnicos trazas, registros y código del informe original
BUG: KASAN: slab-use-after-free in f2fs_truncate_data_blocks_range+0x122a/0x14c0 fs/f2fs/file.c:574 Read of size 4 at addr ffff88802a25c000 by task syz-executor148/5000 CPU: 1 PID: 5000 Comm: syz-executor148 Not tainted 6.4.0-rc7-syzkaller-00041-ge660abd551f1 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351 print_report mm/kasan/report.c:462 [inline] kasan_report+0x11c/0x130 mm/kasan/report.c:572 f2fs_truncate_data_blocks_range+0x122a/0x14c0 fs/f2fs/file.c:574 truncate_dnode+0x229/0x2e0 fs/f2fs/node.c:944 f2fs_truncate_inode_blocks+0x64b/0xde0 fs/f2fs/node.c:1154 f2fs_do_truncate_blocks+0x4ac/0xf30 fs/f2fs/file.c:721 f2fs_truncate_blocks+0x7b/0x300 fs/f2fs/file.c:749 f2fs_truncate.part.0+0x4a5/0x630 fs/f2fs/file.c:799 f2fs_truncate include/linux/fs.h:825 [inline] f2fs_setattr+0x1738/0x2090 fs/f2fs/file.c:1006 notify_change+0xb2c/0x1180 fs/attr.c:483 do_truncate+0x143/0x200 fs/open.c:66 handle_truncate fs/namei.c:3295 [inline] do_open fs/namei.c:3640 [inline] path_openat+0x2083/0x2750 fs/namei.c:3791 do_filp_open+0x1ba/0x410 fs/namei.c:3818 do_sys_openat2+0x16d/0x4c0 fs/open.c:1356 do_sys_open fs/open.c:1372 [inline] __do_sys_creat fs/open.c:1448 [inline] __se_sys_creat fs/open.c:1442 [inline] __x64_sys_creat+0xcd/0x120 fs/open.c:1442 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd
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: 0.17%
- Percentil entre todas las CVEs puntuadas: 6
- 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 escalation85 % - Impacto principal
T1499.004Application or System Exploitationimpact75 % - Impacto secundario
T1565.001Stored Data Manipulationimpact60 %
Vulnerabilidad local de escalada de privilegios (AV:L, PR:L) en kernel Linux f2fs con impacto de confidencialidad, integridad y disponibilidad. El defecto permite acceso fuera de límites a datos de inodos causando corrupción de memoria (use-after-free).
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)
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{
"id": "CVE-2023-53846",
"cveTags": [],
"metrics": {
"cvssMetricV31": [
{
"type": "Secondary",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.8,
"attackVector": "LOCAL",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "LOW",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.9,
"exploitabilityScore": 1.8
}
]
},
"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": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4",
"lessThan": "af0f716ad3b039cab9d426da63a5ee6c88751185",
"versionType": "git"
},
{
"status": "affected",
"version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4",
"lessThan": "a6ec83786ab9f13f25fb18166dee908845713a95",
"versionType": "git"
}
],
"programFiles": [
"fs/f2fs/f2fs.h",
"fs/f2fs/file.c",
"fs/f2fs/node.c",
"include/linux/f2fs_fs.h"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.8"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.4.10",
"versionType": "semver",
"lessThanOrEqual": "6.4.*"
},
{
"status": "unaffected",
"version": "6.5",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/f2fs/f2fs.h",
"fs/f2fs/file.c",
"fs/f2fs/node.c",
"include/linux/f2fs_fs.h"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2025-12-09T16:17:25.003",
"references": [
{
"url": "https://git.kernel.org/stable/c/a6ec83786ab9f13f25fb18166dee908845713a95",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/af0f716ad3b039cab9d426da63a5ee6c88751185",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Deferred",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to do sanity check on direct node in truncate_dnode()\n\nsyzbot reports below bug:\n\nBUG: KASAN: slab-use-after-free in f2fs_truncate_data_blocks_range+0x122a/0x14c0 fs/f2fs/file.c:574\nRead of size 4 at addr ffff88802a25c000 by task syz-executor148/5000\n\nCPU: 1 PID: 5000 Comm: syz-executor148 Not tainted 6.4.0-rc7-syzkaller-00041-ge660abd551f1 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023\nCall Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106\n print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351\n print_report mm/kasan/report.c:462 [inline]\n kasan_report+0x11c/0x130 mm/kasan/report.c:572\n f2fs_truncate_data_blocks_range+0x122a/0x14c0 fs/f2fs/file.c:574\n truncate_dnode+0x229/0x2e0 fs/f2fs/node.c:944\n f2fs_truncate_inode_blocks+0x64b/0xde0 fs/f2fs/node.c:1154\n f2fs_do_truncate_blocks+0x4ac/0xf30 fs/f2fs/file.c:721\n f2fs_truncate_blocks+0x7b/0x300 fs/f2fs/file.c:749\n f2fs_truncate.part.0+0x4a5/0x630 fs/f2fs/file.c:799\n f2fs_truncate include/linux/fs.h:825 [inline]\n f2fs_setattr+0x1738/0x2090 fs/f2fs/file.c:1006\n notify_change+0xb2c/0x1180 fs/attr.c:483\n do_truncate+0x143/0x200 fs/open.c:66\n handle_truncate fs/namei.c:3295 [inline]\n do_open fs/namei.c:3640 [inline]\n path_openat+0x2083/0x2750 fs/namei.c:3791\n do_filp_open+0x1ba/0x410 fs/namei.c:3818\n do_sys_openat2+0x16d/0x4c0 fs/open.c:1356\n do_sys_open fs/open.c:1372 [inline]\n __do_sys_creat fs/open.c:1448 [inline]\n __se_sys_creat fs/open.c:1442 [inline]\n __x64_sys_creat+0xcd/0x120 fs/open.c:1442\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nThe root cause is, inodeA references inodeB via inodeB's ino, once inodeA\nis truncated, it calls truncate_dnode() to truncate data blocks in inodeB's\nnode page, it traverse mapping data from node->i.i_addr[0] to\nnode->i.i_addr[ADDRS_PER_BLOCK() - 1], result in out-of-boundary access.\n\nThis patch fixes to add sanity check on dnode page in truncate_dnode(),\nso that, it can help to avoid triggering such issue, and once it encounters\nsuch issue, it will record newly introduced ERROR_INVALID_NODE_REFERENCE\nerror into superblock, later fsck can detect such issue and try repairing.\n\nAlso, it removes f2fs_truncate_data_blocks() for cleanup due to the\nfunction has only one caller, and uses f2fs_truncate_data_blocks_range()\ninstead."
}
],
"lastModified": "2026-08-04T10:19:23.927",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}