{"id":"CVE-2026-89736","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-89736","summary":"usb: gadget: u_audio: Fix use-after-free on sound card disconnect","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: u_audio: Fix use-after-free on sound card disconnect\n\ng_audio_cleanup() invokes snd_card_free_when_closed() to initiate sound\ncard teardown and immediately frees the underlying struct snd_uac_chip\ncontext. However, snd_card_free_when_closed() returns asynchronously\nwhile ALSA control elements (kctls) remain open in userspace.\n\nWhen userspace control applications access or close these open file\ndescriptors, kctl callbacks attempt to dereference kctl->private_data\npointing to &uac->c_prm or &uac->p_prm within the freed uac structure,\nresulting in a use-after-free (UAF) memory corruption.\n\nFix this issue by deferring the destruction of struct snd_uac_chip until\nall references to the ALSA sound card are released. Register a custom\ncard->private_free callback (u_audio_card_free) during g_audio_setup()\nthat frees uac and its associated playback/capture request and ring\nbuffers only when the sound card reference count drops to zero.","published":"2026-09-11T19:46:44.608Z","modified":"2026-09-14T03:46:33.655819816Z","cvss":{"score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.12.109"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/4e747c864a88537e18b1ffc19a1954c9686bb8e1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/79a92896e2bb9471550c56fc23d8d93592f04c27"},{"type":"WEB","url":"https://git.kernel.org/stable/c/858965947081d10d41d9a1010a540d3d5eea958b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c74ff0b1a0fca53d3ac185873c87d6a719b30a47"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89736.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89736"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-14T03:46:33.655819816Z"}}