{"id":"CVE-2026-98265","summary":"ALSA: usb-audio: Clamp implicit feedback packet count to URB capacity","details":"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-\u003epackets\nisochronous frames, so urb-\u003eiso_frame_desc[] has u-\u003epackets slots and\nctx-\u003epackets 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.","modified":"2026-11-13T04:07:27.289840481Z","published":"2026-10-06T08:45:28.438Z","related":["SUSE-SU-2026:24643-1","SUSE-SU-2026:24648-1","SUSE-SU-2026:24651-1","SUSE-SU-2026:24662-1","openSUSE-SU-2026:12131-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98265.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/6c5c986f761756a6ff7b3aea51c11994fc2464e5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/76a986c980bb502c7688d605ac7a67fd257a9a1b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/79c55a7b5d71cf2a6bbd4bd7698e1b10b70f813a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8b637ab10e40e01b452f4aff66dad335a9b89a16"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ab77e3f453c5f2499c08d6e8e218501d25bab39e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ad279ba0dc1781229f5b52f58d38d56960400e06"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e44cee1bf51e606f3e70a213eb5a1abb3fa56a81"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98265.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98265"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"df75696e70c88b22ed1d8c9d515993a858c58fd0"},{"fixed":"6c5c986f761756a6ff7b3aea51c11994fc2464e5"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3a74f6b46c01d9a816378cd83c327a59f61475ec"},{"fixed":"e44cee1bf51e606f3e70a213eb5a1abb3fa56a81"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c26bde6301f20d9aafbfb7c2459a88c6a6ec178f"},{"fixed":"8b637ab10e40e01b452f4aff66dad335a9b89a16"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"32a1f64f8ff6e2c5391f5964baec697bce25b83c"},{"fixed":"ad279ba0dc1781229f5b52f58d38d56960400e06"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"e949fd266cfa1dcca7caa3faa698578c4ffd26d6"},{"fixed":"79c55a7b5d71cf2a6bbd4bd7698e1b10b70f813a"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"cf044e44190234a41a788de1cdbb6c21f4a52e1e"},{"fixed":"ab77e3f453c5f2499c08d6e8e218501d25bab39e"},{"fixed":"76a986c980bb502c7688d605ac7a67fd257a9a1b"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"f6fbdf797e016fbf968dd54301026b182175985a"}]}],"versions":["v5.15.223","v5.15.222","v5.15.221","v5.15.220","v5.15.219","v5.15.218","v5.15.217","v5.15.216","v5.15.215","v5.15.214","v5.15.213","v5.15.212","v5.15.211","v5.15.210","v5.15.209","v5.15.208","v5.15.207","v5.15.206","v5.15.205","v5.15.204","v5.15.203","v5.15.202","v6.1.190","v6.1.189","v6.1.188","v6.1.187","v6.1.186","v6.1.185","v6.1.184","v6.1.183","v6.1.182","v6.1.181","v6.1.180","v6.1.179","v6.1.178","v6.1.177","v6.1.176","v6.1.175","v6.1.174","v6.1.173","v6.1.172","v6.1.171","v6.1.170","v6.1.169","v6.1.168","v6.1.167","v6.1.166","v6.1.165","v6.6.159","v6.6.158","v6.6.157","v6.6.156","v6.6.155","v6.6.154","v6.6.153","v6.6.152","v6.6.151","v6.6.150","v6.6.149","v6.6.148","v6.6.147","v6.6.146","v6.6.145","v6.6.144","v6.6.143","v6.6.142","v6.6.141","v6.6.140","v6.6.139","v6.6.138","v6.6.137","v6.6.136","v6.6.135","v6.6.134","v6.6.133","v6.6.132","v6.6.131","v6.6.130","v6.6.129","v6.6.128","v6.12.111","v6.12.110","v6.12.109","v6.12.108","v6.12.107","v6.12.106","v6.12.105","v6.12.104","v6.12.103","v6.12.102","v6.12.101","v6.12.100","v6.12.99","v6.12.98","v6.12.97","v6.12.96","v6.12.95","v6.12.94","v6.12.93","v6.12.92","v6.12.91","v6.12.90","v6.12.89","v6.12.88","v6.12.87","v6.12.86","v6.12.85","v6.12.84","v6.12.83","v6.12.82","v6.12.81","v6.12.80","v6.12.79","v6.12.78","v6.12.77","v6.12.76","v6.12.75","v6.18.53","v6.18.52","v6.18.51","v6.18.50","v6.18.49","v6.18.48","v6.18.47","v6.18.46","v6.18.45","v6.18.44","v6.18.43","v6.18.42","v6.18.41","v6.18.40","v6.18.39","v6.18.38","v6.18.37","v6.18.36","v6.18.35","v6.18.34","v6.18.33","v6.18.32","v6.18.31","v6.18.30","v6.18.29","v6.18.28","v6.18.27","v6.18.26","v6.18.25","v6.18.24","v6.18.23","v6.18.22","v6.18.21","v6.18.20","v6.18.19","v6.18.18","v6.18.17","v6.18.16","v6.19.14","v6.19.13","v6.19.12","v6.19.11","v6.19.10","v6.19.9","v6.19.8","v6.19.7","v6.19.6"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-98265.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.15.202"},{"fixed":"5.15.224"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.1.165"},{"fixed":"6.1.191"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.6.128"},{"fixed":"6.6.160"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.12.75"},{"fixed":"6.12.112"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.18.16"},{"fixed":"6.18.54"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.6"},{"fixed":"6.20"}]},{"type":"ECOSYSTEM","events":[{"introduced":"7.0.0"},{"fixed":"7.2.8"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-98265.json"}}],"schema_version":"1.9.2"}