CVE-2026-99271
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: ALSA: line6: Clear prev_fbuf on capture buffer release A KASAN slab-use-after-free read was reported in submit_audio_out_urb() when generating an impulse test signal: BUG: KASAN: slab-use-after-free in create_impulse_test_signal sound/usb/line6/playback.c:76 [inline] BUG: KASAN: slab-use-after-free in submit_audio_out_urb+0x1848/0x1b20 sound/usb/line6/playback.c:249 Read of size 2 at addr ffff888008d74870 by task syz.2.3214/7785 Allocated by task 11: kmem_cache_alloc_noprof+0x2f0/0x390 mm/slub.c:4144 line6_buffer_acquire+0x1a1/0x220 sound/usb/line6/pcm.c:158 line6_pcm_acquire+0xb6/0x230 sound/usb/line6/pcm.c:329 line6_startup_work+0x3c/0x50 sound/usb/line6/driver.c:728 Freed by task 7785: kfree+0xf8/0x390 mm/slub.c:6566 line6_buffer_release sound/usb/line6/pcm.c:176 [inline] line6_buffer_release+0xa5/0xf0 sound/usb/line6/pcm.c:170 __line6_pcm_release sound/usb/line6/pcm.c:305 [inline] line6_pcm_release+0x5a/0x80 sound/usb/line6/pcm.c:313 snd_toneport_monitor_put+0x11b/0x190 sound/usb/line6/toneport.c:183 line6pcm->prev_fbuf points into the capture PCM stream buffer (line6pcm->in.buffer), which is updated during audio_in_callback() to feed rate synchronization, software monitoring, and impulse test signal generation on playback side. When all capture streams are closed, line6_buffer_release() frees pstr->buffer with kfree(). However, it does not clear line6pcm->prev_fbuf. If playback is subsequently started (e.g. via impulse test signal volume control snd_line6_impulse_volume_put()), submit_audio_out_urb() dereferences the stale pointer line6pcm->prev_fbuf under in.lock, resulting in a slab-use-after-free read. Clear prev_fbuf and prev_fsize in line6_buffer_release() when releasing the capture stream buffer under in.lock, ensuring that no stale buffer pointer can be accessed by submit_audio_out_urb().
View original CVE JSON
{
"id": "CVE-2026-99271",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-11-07T14:17:02.337",
"lastModified": "2026-11-07T14:17:02.337",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: line6: Clear prev_fbuf on capture buffer release\n\nA KASAN slab-use-after-free read was reported in submit_audio_out_urb()\nwhen generating an impulse test signal:\n\n BUG: KASAN: slab-use-after-free in create_impulse_test_signal sound/usb/line6/playback.c:76 [inline]\n BUG: KASAN: slab-use-after-free in submit_audio_out_urb+0x1848/0x1b20 sound/usb/line6/playback.c:249\n Read of size 2 at addr ffff888008d74870 by task syz.2.3214/7785\n\n Allocated by task 11:\n kmem_cache_alloc_noprof+0x2f0/0x390 mm/slub.c:4144\n line6_buffer_acquire+0x1a1/0x220 sound/usb/line6/pcm.c:158\n line6_pcm_acquire+0xb6/0x230 sound/usb/line6/pcm.c:329\n line6_startup_work+0x3c/0x50 sound/usb/line6/driver.c:728\n\n Freed by task 7785:\n kfree+0xf8/0x390 mm/slub.c:6566\n line6_buffer_release sound/usb/line6/pcm.c:176 [inline]\n line6_buffer_release+0xa5/0xf0 sound/usb/line6/pcm.c:170\n __line6_pcm_release sound/usb/line6/pcm.c:305 [inline]\n line6_pcm_release+0x5a/0x80 sound/usb/line6/pcm.c:313\n snd_toneport_monitor_put+0x11b/0x190 sound/usb/line6/toneport.c:183\n\nline6pcm->prev_fbuf points into the capture PCM stream buffer\n(line6pcm->in.buffer), which is updated during audio_in_callback() to\nfeed rate synchronization, software monitoring, and impulse test signal\ngeneration on playback side.\n\nWhen all capture streams are closed, line6_buffer_release() frees\npstr->buffer with kfree(). However, it does not clear line6pcm->prev_fbuf.\nIf playback is subsequently started (e.g. via impulse test signal\nvolume control snd_line6_impulse_volume_put()), submit_audio_out_urb()\ndereferences the stale pointer line6pcm->prev_fbuf under in.lock,\nresulting in a slab-use-after-free read.\n\nClear prev_fbuf and prev_fsize in line6_buffer_release() when releasing\nthe capture stream buffer under in.lock, ensuring that no stale buffer\npointer can be accessed by submit_audio_out_urb()."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"sound/usb/line6/pcm.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "63e20df1e5b2ef8d871ecbdb6c038d554ed1ca74",
"lessThan": "862d9268f40a6e10cef24eb226e738fb69ce8aa7",
"versionType": "git",
"status": "affected"
},
{
"version": "63e20df1e5b2ef8d871ecbdb6c038d554ed1ca74",
"lessThan": "22c82f33ff0b68d37041adf1dea5533a5863cd31",
"versionType": "git",
"status": "affected"
},
{
"version": "63e20df1e5b2ef8d871ecbdb6c038d554ed1ca74",
"lessThan": "aa118c8f61d59387961d58ffae831c5259a9f222",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"sound/usb/line6/pcm.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "4.0",
"status": "affected"
},
{
"version": "0",
"lessThan": "4.0",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.61",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.3.2",
"lessThanOrEqual": "7.3.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.4-rc1",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/22c82f33ff0b68d37041adf1dea5533a5863cd31",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/862d9268f40a6e10cef24eb226e738fb69ce8aa7",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/aa118c8f61d59387961d58ffae831c5259a9f222",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}