CVE-2025-39993
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: media: rc: fix races with imon_disconnect() Syzbot reports a KASAN issue as below: BUG: KASAN: use-after-free in __create_pipe include/linux/usb.h:1945 [inline] BUG: KASAN: use-after-free in send_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627 Read of size 4 at addr ffff8880256fb000 by task syz-executor314/4465 CPU: 2 PID: 4465 Comm: syz-executor314 Not tainted 6.0.0-rc1-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x6e9 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 __create_pipe include/linux/usb.h:1945 [inline] send_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627 vfd_write+0x2d9/0x550 drivers/media/rc/imon.c:991 vfs_write+0x2d7/0xdd0 fs/read_write.c:576 ksys_write+0x127/0x250 fs/read_write.c:631 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The iMON driver improperly releases the usb_device reference in imon_disconnect without coordinating with active users of the device. Specifically, the fields usbdev_intf0 and usbdev_intf1 are not protected by the users counter (ictx->users). During probe, imon_init_intf0 or imon_init_intf1 increments the usb_device reference count depending on the interface. However, during disconnect, usb_put_dev is called unconditionally, regardless of actual usage. As a result, if vfd_write or other operations are still in progress after disconnect, this can lead to a use-after-free of the usb_device pointer. Thread 1 vfd_write Thread 2 imon_disconnect ... if usb_put_dev(ictx->usbdev_intf0) else usb_put_dev(ictx->usbdev_intf1) ... while send_packet if pipe = usb_sndintpipe( ictx->usbdev_intf0) UAF else pipe = usb_sndctrlpipe( ictx->usbdev_intf0, 0) UAF Guard access to usbdev_intf0 and usbdev_intf1 after disconnect by checking ictx->disconnected in all writer paths. Add early return with -ENODEV in send_packet(), vfd_write(), lcd_write() and display_open() if the device is no longer present. Set and read ictx->disconnected under ictx->lock to ensure memory synchronization. Acquire the lock in imon_disconnect() before setting the flag to synchronize with any ongoing operations. Ensure writers exit early and safely after disconnect before the USB core proceeds with cleanup. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
View original CVE JSON
{
"id": "CVE-2025-39993",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2025-10-15T08:15:37.443",
"lastModified": "2026-10-19T21:10:00.160",
"vulnStatus": "Deferred",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: rc: fix races with imon_disconnect()\n\nSyzbot reports a KASAN issue as below:\nBUG: KASAN: use-after-free in __create_pipe include/linux/usb.h:1945 [inline]\nBUG: KASAN: use-after-free in send_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627\nRead of size 4 at addr ffff8880256fb000 by task syz-executor314/4465\n\nCPU: 2 PID: 4465 Comm: syz-executor314 Not tainted 6.0.0-rc1-syzkaller #0\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014\nCall Trace:\n <TASK>\n__dump_stack lib/dump_stack.c:88 [inline]\ndump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106\nprint_address_description mm/kasan/report.c:317 [inline]\nprint_report.cold+0x2ba/0x6e9 mm/kasan/report.c:433\nkasan_report+0xb1/0x1e0 mm/kasan/report.c:495\n__create_pipe include/linux/usb.h:1945 [inline]\nsend_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627\nvfd_write+0x2d9/0x550 drivers/media/rc/imon.c:991\nvfs_write+0x2d7/0xdd0 fs/read_write.c:576\nksys_write+0x127/0x250 fs/read_write.c:631\ndo_syscall_x64 arch/x86/entry/common.c:50 [inline]\ndo_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80\nentry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nThe iMON driver improperly releases the usb_device reference in\nimon_disconnect without coordinating with active users of the\ndevice.\n\nSpecifically, the fields usbdev_intf0 and usbdev_intf1 are not\nprotected by the users counter (ictx->users). During probe,\nimon_init_intf0 or imon_init_intf1 increments the usb_device\nreference count depending on the interface. However, during\ndisconnect, usb_put_dev is called unconditionally, regardless of\nactual usage.\n\nAs a result, if vfd_write or other operations are still in\nprogress after disconnect, this can lead to a use-after-free of\nthe usb_device pointer.\n\nThread 1 vfd_write Thread 2 imon_disconnect\n ...\n if\n usb_put_dev(ictx->usbdev_intf0)\n else\n usb_put_dev(ictx->usbdev_intf1)\n...\nwhile\n send_packet\n if\n pipe = usb_sndintpipe(\n ictx->usbdev_intf0) UAF\n else\n pipe = usb_sndctrlpipe(\n ictx->usbdev_intf0, 0) UAF\n\nGuard access to usbdev_intf0 and usbdev_intf1 after disconnect by\nchecking ictx->disconnected in all writer paths. Add early return\nwith -ENODEV in send_packet(), vfd_write(), lcd_write() and\ndisplay_open() if the device is no longer present.\n\nSet and read ictx->disconnected under ictx->lock to ensure memory\nsynchronization. Acquire the lock in imon_disconnect() before setting\nthe flag to synchronize with any ongoing operations.\n\nEnsure writers exit early and safely after disconnect before the USB\ncore proceeds with cleanup.\n\nFound by Linux Verification Center (linuxtesting.org) with Syzkaller."
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nmedia: rc: corregir condiciones de carrera con imon_disconnect()\n\nSyzbot informa un problema de KASAN como se detalla a continuación:\nERROR: KASAN: uso después de liberación en __create_pipe include/linux/usb.h:1945 [en línea]\nERROR: KASAN: uso después de liberación en send_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627\nLectura de tamaño 4 en la dirección ffff8880256fb000 por la tarea syz-executor314/4465\n\nCPU: 2 PID: 4465 Comm: syz-executor314 No contaminado 6.0.0-rc1-syzkaller #0\nNombre del hardware: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014\nRastro de Llamada:\n <TAREA>\n__dump_stack lib/dump_stack.c:88 [en línea]\ndump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106\nprint_address_description mm/kasan/report.c:317 [en línea]\nprint_report.cold+0x2ba/0x6e9 mm/kasan/report.c:433\nkasan_report+0xb1/0x1e0 mm/kasan/report.c:495\n__create_pipe include/linux/usb.h:1945 [en línea]\nsend_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627\nvfd_write+0x2d9/0x550 drivers/media/rc/imon.c:991\nvfs_write+0x2d7/0xdd0 fs/read_write.c:576\nksys_write+0x127/0x250 fs/read_write.c:631\ndo_syscall_x64 arch/x86/entry/common.c:50 [en línea]\ndo_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80\nentry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nEl controlador iMON libera incorrectamente la referencia usb_device en\nimon_disconnect sin coordinarse con los usuarios activos del\ndispositivo.\n\nEspecíficamente, los campos usbdev_intf0 y usbdev_intf1 no están\nprotegidos por el contador de usuarios (ictx->users). Durante la sonda,\nimon_init_intf0 o imon_init_intf1 incrementa el contador de referencias de usb_device\ndependiendo de la interfaz. Sin embargo, durante la\ndesconexión, usb_put_dev se llama incondicionalmente, independientemente del\nuso real.\n\nComo resultado, si vfd_write u otras operaciones todavía están en\ncurso después de la desconexión, esto puede llevar a un uso después de liberación del\npuntero usb_device.\n\nHilo 1 vfd_write Hilo 2 imon_disconnect\n ...\n si\n usb_put_dev(ictx->usbdev_intf0)\n sino\n usb_put_dev(ictx->usbdev_intf1)\n...\nmientras\n send_packet\n si\n pipe = usb_sndintpipe(\n ictx->usbdev_intf0) UAF\n sino\n pipe = usb_sndctrlpipe(\n ictx->usbdev_intf0, 0) UAF\n\nProteger el acceso a usbdev_intf0 y usbdev_intf1 después de la desconexión\ncomprobando ictx->disconnected en todas las rutas de escritura. Añadir un retorno\nanticipado con -ENODEV en send_packet(), vfd_write(), lcd_write() y\ndisplay_open() si el dispositivo ya no está presente.\n\nEstablecer y leer ictx->disconnected bajo ictx->lock para asegurar la\nsincronización de la memoria. Adquirir el bloqueo en imon_disconnect() antes de\nestablecer la bandera para sincronizar con cualquier operación en curso.\n\nAsegurar que los escritores salgan anticipada y seguramente después de la\ndesconexión antes de que el núcleo USB proceda con la limpieza.\n\nEncontrado por Linux Verification Center (linuxtesting.org) con Syzkaller."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"drivers/media/rc/imon.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
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"lessThan": "9348976003e39754af344949579e824a0a210fc4",
"versionType": "git",
"status": "affected"
},
{
"version": "21677cfc562a27e099719d413287bc8d1d24deb7",
"lessThan": "b03fac6e2a38331faf8510b480becfa90cea1c9f",
"versionType": "git",
"status": "affected"
},
{
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"lessThan": "71c52b073922d05e79e6de7fc7f5f38f927929a4",
"versionType": "git",
"status": "affected"
},
{
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"lessThan": "71096a6161a25e84acddb89a9d77f138502d26ab",
"versionType": "git",
"status": "affected"
},
{
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"versionType": "git",
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},
{
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"lessThan": "fd5d3e6b149ec8cce045d86a2b5e3664d6b32ba5",
"versionType": "git",
"status": "affected"
},
{
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"lessThan": "d9f6ce99624a41c3bcb29a8d7d79b800665229dd",
"versionType": "git",
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},
{
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"lessThan": "2e7fd93b9cc565b839bc55a6662475718963e156",
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},
{
"version": "21677cfc562a27e099719d413287bc8d1d24deb7",
"lessThan": "fa0f61cc1d828178aa921475a9b786e7fbb65ccb",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"drivers/media/rc/imon.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "2.6.35",
"status": "affected"
},
{
"version": "0",
"lessThan": "2.6.35",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.4.301",
"lessThanOrEqual": "5.4.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.10.246",
"lessThanOrEqual": "5.10.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.15.195",
"lessThanOrEqual": "5.15.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.156",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.110",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.51",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.16.11",
"lessThanOrEqual": "6.16.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.17.1",
"lessThanOrEqual": "6.17.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-06-16T16:12:54.804332Z",
"id": "CVE-2025-39993",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"references": [
{
"url": "https://git.kernel.org/stable/c/2e7fd93b9cc565b839bc55a6662475718963e156",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
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{
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{
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}
]
}