CVE-2026-74498

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

ALSA: usb-audio: Fix DMA buffer out-of-bounds write when fill_max is set

When a USB audio endpoint requests full packet transfers via the fill_max

descriptor flag, data_ep_set_params() promotes ep->curpacksize to

ep->maxpacksize. However, maxsize is left at the original sample-rate

derived value.

Since u->buffer_size is allocated as maxsize * packets, the resulting

DMA buffer is far too small for the requested transfer length. When the

USB host controller streams up to curpacksize bytes per packet, it writes

past the end of the buffer via DMA, corrupting kernel heap memory.

Update maxsize to curpacksize when fill_max is set so that the allocated

DMA buffer size matches the actual transfer request size.

[ changed to reassign maxsize only when ep->fill_max is set -- tiwai ]

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References