{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89736", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.761Z", "datePublished": "2026-09-11T19:46:44.608Z", "dateUpdated": "2026-10-19T08:51:50.340Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:51:50.340Z" }, "descriptions": [ { "lang": "en", "value": "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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The UAF is reached from local userspace: configfs UDC unbind calls afunc_unbind/f_audio_unbind → g_audio_cleanup, which frees snd_uac_chip while ALSA kctl/PCM fds still reference it; g_audio_setup runs at function bind with no USB host required, matching gadget teardown scores such as CVE-2024-38628.\nAC:L - The attacker controls both sides by issuing SNDRV_CTL_IOCTL_ELEM_READ/WRITE on the UAC mixer kctls while concurrently unbinding the gadget; snd_card_disconnect does not drain in-flight ioctls before g_audio_cleanup kfree()s the chip, so kctl get/put callbacks dereference freed uac_rtd_params and the race is freely retryable.\nPR:L - Android and embedded USB gadget HALs commonly delegate /sys/kernel/config/usb_gadget UDC writes to non-root service accounts, and the UAC gadget's ALSA control/PCM nodes are reachable by unprivileged local users; init-namespace root is not required once the gadget is deployed.\nUI:N - The attacker performs gadget unbind, holds ALSA fds, and issues mixer ioctls itself; no separate victim action such as plugging a cable or mounting a filesystem is required.\nS:U - The use-after-free corrupts kernel heap objects (snd_uac_chip and its playback/capture rings) within the same host kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Kctl get/info/tlv callbacks (u_audio_volume_get, u_audio_rate_get, u_audio_volume_tlv) read volume, rate, and TLV fields from the already-freed snd_uac_chip and copy them to userspace, yielding a use-after-free disclosure primitive that kernel scoring treats as High confidentiality.\nI:H - Kctl put callbacks (u_audio_volume_put, u_audio_mute_put, u_audio_pitch_put) take prm->lock and write volume/mute/pitch into the kfree()'d snd_uac_chip, providing a write-after-free primitive that can be turned into arbitrary write or control-flow hijack.\nA:H - Use of the freed snd_uac_chip, including spin_lock_irqsave on prm->lock and USB ISO completions with req->context pointing into the freed object, reliably produces KASAN reports, oops, and kernel panic." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/usb/gadget/function/u_audio.c" ], "versions": [ { "version": "33f341c1fc60e172a3515c51bdabee11e83d1ee9", "lessThan": "a7ecd1a04f4f485d7be6443d0f0b2c61a800cb82", "status": "affected", "versionType": "git" }, { "version": "b131989797f7287d7fdadb2bababc05a15d44750", "lessThan": "f983793f03148b097977f200298db215cd2d4438", "status": "affected", "versionType": "git" }, { "version": "3bc7324e4911351e39c54a62e6ca46321cb10faf", "lessThan": "6f46762196f04464e1050a9ee94e72b917db9010", "status": "affected", "versionType": "git" }, { "version": "6c67ed9ad9b83e453e808f9b31a931a20a25629b", "lessThan": "891a8d11f4d5eb50b2ce7570f4f98204a7a57493", "status": "affected", "versionType": "git" }, { "version": "6c67ed9ad9b83e453e808f9b31a931a20a25629b", "lessThan": "c74ff0b1a0fca53d3ac185873c87d6a719b30a47", "status": "affected", "versionType": "git" }, { "version": "6c67ed9ad9b83e453e808f9b31a931a20a25629b", "lessThan": "4e747c864a88537e18b1ffc19a1954c9686bb8e1", "status": "affected", "versionType": "git" }, { "version": "6c67ed9ad9b83e453e808f9b31a931a20a25629b", "lessThan": "79a92896e2bb9471550c56fc23d8d93592f04c27", "status": "affected", "versionType": "git" }, { "version": "6c67ed9ad9b83e453e808f9b31a931a20a25629b", "lessThan": "858965947081d10d41d9a1010a540d3d5eea958b", "status": "affected", "versionType": "git" }, { "version": "3e016ef2e72da93a2ea7afbb45de1b481b44d761", "status": "affected", "versionType": "git" }, { "version": "3256e152b645fc1e788ba44c2d8ced690113e3e6", "status": "affected", "versionType": "git" }, { "version": "0eda2004f38d95ef5715d62be884cd344260535b", "status": "affected", "versionType": "git" }, { "version": "43ca70753dfffd517d2af126da28690f8f615605", "status": "affected", "versionType": "git" }, { "version": "5.10.177", "lessThan": "5.10.270", "status": "affected", "versionType": "semver" }, { "version": "5.15.105", "lessThan": "5.15.221", "status": "affected", "versionType": "semver" }, { "version": "6.1.22", "lessThan": "6.1.188", "status": "affected", "versionType": "semver" }, { "version": "4.14.312", "lessThan": "4.15", "status": "affected", "versionType": "semver" }, { "version": "4.19.280", "lessThan": "4.20", "status": "affected", "versionType": "semver" }, { "version": "5.4.240", "lessThan": "5.5", "status": "affected", "versionType": "semver" }, { "version": "6.2.9", "lessThan": "6.3", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/usb/gadget/function/u_audio.c" ], "versions": [ { "version": "6.3", "status": "affected" }, { "version": "0", "lessThan": "6.3", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.270", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.177", "versionEndExcluding": "5.10.270" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.105", "versionEndExcluding": "5.15.221" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.22", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.12.109" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "7.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14.312" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19.280" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4.240" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2.9" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/a7ecd1a04f4f485d7be6443d0f0b2c61a800cb82" }, { "url": "https://git.kernel.org/stable/c/f983793f03148b097977f200298db215cd2d4438" }, { "url": "https://git.kernel.org/stable/c/6f46762196f04464e1050a9ee94e72b917db9010" }, { "url": "https://git.kernel.org/stable/c/891a8d11f4d5eb50b2ce7570f4f98204a7a57493" }, { "url": "https://git.kernel.org/stable/c/c74ff0b1a0fca53d3ac185873c87d6a719b30a47" }, { "url": "https://git.kernel.org/stable/c/4e747c864a88537e18b1ffc19a1954c9686bb8e1" }, { "url": "https://git.kernel.org/stable/c/79a92896e2bb9471550c56fc23d8d93592f04c27" }, { "url": "https://git.kernel.org/stable/c/858965947081d10d41d9a1010a540d3d5eea958b" } ], "title": "usb: gadget: u_audio: Fix use-after-free on sound card disconnect", "x_generator": { "engine": "bippy-1.2.0" } } } }