CVE-2026-23208: ALSA: usb-audio: Prevent excessive number of frames

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-02-14 · updated 2026-10-30
Weakness: CWE-787

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Prevent excessive number of frames In this case, the user constructed the parameters with maxpacksize 40 for rate 22050 / pps 1000, and packsize[0] 22 packsize[1] 23. The buffer size for each data URB is maxpacksize * packets, which in this example is 40 * 6 = 240; When the user performs a write operation to send audio data into the ALSA PCM playback stream, the calculated number of frames is packsize[0] * packets = 264, which exceeds the allocated URB buffer size, triggering the out-of-bounds (OOB) issue reported by syzbot [1]. Added a check for the number of single data URB frames when calculating the number of frames to prevent [1]. [1] BUG: KASAN: slab-out-of-bounds in copy_to_urb+0x261/0x460 sound/usb/pcm.c:1487 Write of size 264 at addr ffff88804337e800 by task syz.0.17/5506 Call Trace: copy_to_urb+0x261/0x460 sound/usb/pcm.c:1487 prepare_playback_urb+0x953/0x13d0 sound/usb/pcm.c:1611 prepare_outbound_urb+0x377/0xc50 sound/usb/endpoint.c:333

Affected products

Linux kernel: from 4.14.186 before 4.14.188; from 4.19.130 before 4.19.132; from 5.4.49 before 5.4.51; from 5.7.6 before 5.7.8; from 5.8 before 6.18.10; 6.19-rc1, 6.19-rc2, 6.19-rc3, 6.19-rc4, 6.19-rc5 — fixed in 4.14.188, 4.19.132, 5.4.51, 5.7.8, 6.18.10
Linux: from 4.4.229 before 4.4.230; from 4.9.229 before 4.9.230; from 4.14.186 before 4.14.188; from 4.19.130 before 4.19.132; from 5.4.49 before 5.4.51; from 5.7.6 before 5.7.8 — fixed in 4.4.230, 4.9.230, 4.14.188, 4.19.132, 5.4.51, 5.7.8

How to fix

Upgrade to a fixed version: Linux kernel 4.14.188, 4.19.132, 5.4.51, 5.7.8; Linux 4.4.230, 4.9.230, 4.14.188, 4.19.132. Check the vendor advisory for mitigations.

References

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