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

Vulnerability summary

CVE-2026-23208 is a high (CVSS 7.8) Out-of-bounds Write vulnerability in linux. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 8.2% of scored vulnerabilities.

Timeline

1. 14-02-2026
   PublishedVulnerability first disclosed.
2. 30-10-2026
   Last modifiedVulnerability information updated.

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

• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.