{"id":"CVE-2026-98265","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: usb-audio: Clamp implicit feedback packet count to URB capacity\n\ndata_ep_set_params() allocates each data URB for exactly u->packets\nisochronous frames, so urb->i…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: usb-audio: Clamp implicit feedback packet count to URB capacity\n\ndata_ep_set_params() allocates each data URB for exactly u->packets\nisochronous frames, so urb->i…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 32a1f64f8ff6e2c5391f5964baec697bce25b83c < ad279ba0dc1781229f5b52f58d38d56960400e06","Linux >= e949fd266cfa1dcca7caa3faa698578c4ffd26d6 < 79c55a7b5d71cf2a6bbd4bd7698e1b10b70f813a","Linux >= cf044e44190234a41a788de1cdbb6c21f4a52e1e < ab77e3f453c5f2499c08d6e8e218501d25bab39e","Linux >= cf044e44190234a41a788de1cdbb6c21f4a52e1e < 76a986c980bb502c7688d605ac7a67fd257a9a1b","Linux df75696e70c88b22ed1d8c9d515993a858c58fd0","Linux 3a74f6b46c01d9a816378cd83c327a59f61475ec","Linux c26bde6301f20d9aafbfb7c2459a88c6a6ec178f","Linux f6fbdf797e016fbf968dd54301026b182175985a","Linux >= 6.12.75 < 6.12.112","Linux >= 6.18.16 < 6.18.54","Linux >= 5.15.202 < 5.16","Linux >= 6.1.165 < 6.2","Linux >= 6.6.128 < 6.7","Linux >= 6.19.6 < 6.20","Linux 7.0"],"published":"2026-10-06","updated":"2026-10-06","sourceUpdated":"2026-10-06T09:18:15.797","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98265","references":[{"url":"https://git.kernel.org/stable/c/76a986c980bb502c7688d605ac7a67fd257a9a1b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/79c55a7b5d71cf2a6bbd4bd7698e1b10b70f813a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ab77e3f453c5f2499c08d6e8e218501d25bab39e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ad279ba0dc1781229f5b52f58d38d56960400e06","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-10-06T08:50:17.426Z","slug":"CVE-2026-98265","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nALSA: usb-audio: Clamp implicit feedback packet count to URB capacity\n\ndata_ep_set_params() allocates each data URB for exactly u->packets\nisochronous frames, so urb->iso_frame_desc[] has u->packets slots and\nctx->packets is the driver's only record of that limit. For an implicit\nfeedback sink, snd_usb_queue_pending_output_urbs() overwrites it with the\nsync source's packet count, which is calculated independently from the\ncapture endpoint's parameters. When that count is larger,\nprepare_playback_urb() and prepare_silent_urb() can write\niso_frame_desc[] past the allocation; their existing bounds limit payload\nbytes, not the descriptor index.\n\nThe reproducer uses a high-speed UAC2 device declaring bInterval 1 for\nimplicit feedback capture (8 packets) and bInterval 4 for playback\n(1 packet). On the first capture completion after the stream starts, it\naccesses seven descriptors spanning 112 bytes beyond the one-packet URB:\n\n  BUG: KASAN: slab-out-of-bounds in prepare_playback_urb (sound/usb/pcm.c:1560)\n  Write of size 4 at addr ffff88801e696ad0 by task vhci_rx/178\n   prepare_playback_urb (sound/usb/pcm.c:1560)\n   prepare_outbound_urb (sound/usb/endpoint.c:340)\n   snd_usb_queue_pending_output_urbs (sound/usb/endpoint.c:501)\n   snd_complete_urb (sound/usb/endpoint.c:1834)\n   __usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1657)\n   usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1741)\n   vhci_rx_loop (drivers/usb/usbip/vhci_rx.c:107)\n   kthread (kernel/kthread.c:436)\n  The buggy address belongs to the object at ffff88801e696a00\n   which belongs to the cache kmalloc-256 of size 256\n  The buggy address is located 0 bytes to the right of\n   allocated 208-byte region [ffff88801e696a00, ffff88801e696ad0)\n\nRecord the allocated packet count per endpoint and clamp both the adopted\ncount and the packet-size copy to it. Fold the Format Type II delimiter\ninto urb_packs before the allocation loop so the recorded limit matches\nevery URB.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}