Linux Kernel up to 6.18.9 ALSA copy_to_urb out-of-bounds

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.18.9 and classified as critical. The impacted element is the function copy_to_urb of the component ALSA. The manipulation results in out-of-bounds. This vulnerability is identified as CVE-2026-23208. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.9. It has been classified as problematic. Affected is the function copy_to_urb of the component ALSA. The manipulation with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality. CVE summarizes:

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

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-23208 since 01/13/2026. The exploitability is told to be difficult. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 299122 (Linux Distros Unpatched Vulnerability : CVE-2026-23208), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.10 eliminates this vulnerability. Applying the patch 62932d9ed639a9fa71b4ac1a56766a4b43abb7e4/ef5749ef8b307bf8717945701b1b79d036af0a15 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (299122) and EUVD (EUVD-2026-6106). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion