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().
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Sat, 07 Nov 2026 16:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200
CWE-416

Sat, 07 Nov 2026 14:15:00 +0000

Type Values Removed Values Added
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().
Title ALSA: line6: Clear prev_fbuf on capture buffer release
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-11-07T14:08:45.047Z

Reserved: 2026-09-25T10:25:14.404Z

Link: CVE-2026-99271

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-07T14:17:02.337

Modified: 2026-11-07T14:17:02.337

Link: CVE-2026-99271

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-07T16:00:17Z

Weaknesses