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CVE-2026-89736— usb: gadget: u_audio: Fix use-after-free on sound card disconnect

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linux 内核中，以下漏洞已得到修复： usb: gadget: u_audio: 修复声卡断开连接时的释放后使用（Use-After-Free）问题 函数调用 来启动声卡的拆除过程，并立即释放底层的 上下文。然而， 是异步返回的，而用户空间中的 ALSA 控制元素（kctls）仍处于打开状态。 当用户空间的控制程序访问或关闭这些已打开的文件描述符时，kctl 回调函数试图解引用指向 或 的 。由于指向已释放的 结构体，导致了释放后使用（Use-After-Free, UAF）内存破坏。 修复方法： 通过延迟

AI Predicted 7.0 Difficulty: Moderate

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 24

VendorProduct Version RangeStatus
Linux Linux 6c67ed9ad9b83e453e808f9b31a931a20a25629b< c74ff0b1a0fca53d3ac185873c87d6a719b30a47 affected
6c67ed9ad9b83e453e808f9b31a931a20a25629b< 4e747c864a88537e18b1ffc19a1954c9686bb8e1 affected
6c67ed9ad9b83e453e808f9b31a931a20a25629b< 79a92896e2bb9471550c56fc23d8d93592f04c27 affected
6c67ed9ad9b83e453e808f9b31a931a20a25629b< 858965947081d10d41d9a1010a540d3d5eea958b affected
3e016ef2e72da93a2ea7afbb45de1b481b44d761 affected
3256e152b645fc1e788ba44c2d8ced690113e3e6 affected
0eda2004f38d95ef5715d62be884cd344260535b affected
33f341c1fc60e172a3515c51bdabee11e83d1ee9 affected
… +16 more rows
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I. Basic Information for CVE-2026-89736

Vulnerability Information
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Vulnerability Title
usb: gadget: u_audio: Fix use-after-free on sound card disconnect
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: u_audio: Fix use-after-free on sound card disconnect g_audio_cleanup() invokes snd_card_free_when_closed() to initiate sound card teardown and immediately frees the underlying struct snd_uac_chip context. However, snd_card_free_when_closed() returns asynchronously while ALSA control elements (kctls) remain open in userspace. When userspace control applications access or close these open file descriptors, kctl callbacks attempt to dereference kctl->private_data pointing to &uac->c_prm or &uac->p_prm within the freed uac structure, resulting in a use-after-free (UAF) memory corruption. Fix this issue by deferring the destruction of struct snd_uac_chip until all references to the ALSA sound card are released. Register a custom card->private_free callback (u_audio_card_free) during g_audio_setup() that frees uac and its associated playback/capture request and ring buffers only when the sound card reference count drops to zero.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 6c67ed9ad9b83e453e808f9b31a931a20a25629b ~ c74ff0b1a0fca53d3ac185873c87d6a719b30a47 -
Linux Linux 6.3 -

II. Public POCs for CVE-2026-89736

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III. Intelligence Information for CVE-2026-89736

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Other References for CVE-2026-89736 (4)

Same Patch Batch · Linux · 2026-09-11 · 431 CVEs total

CVE-2026-89491 ocfs2: cluster: don't sleep while holding o2hb_live_lock in o2hb_region_pin()
CVE-2026-89477 sctp: fix NULL deref on untransmitted RECONF completion
CVE-2026-89478 sctp: drop a chunk if its transport was removed
CVE-2026-89479 sctp: stop processing a packet once its association is deleted
CVE-2026-89480 nvme-tcp: reject a read that transferred too few bytes
CVE-2026-89482 nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone
CVE-2026-89481 nvme-tcp: fix host memory disclosure on R2T for a read command
CVE-2026-89483 nvme: zero the discard fallback page
CVE-2026-89484 lockd: fix NULL dereference on lockowner allocation failure
CVE-2026-89485 lockd: pin next file across nlm_inspect_file lock-drop
CVE-2026-89486 ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()
CVE-2026-89487 openvswitch: only skb_tx_error() a packet we are about to drop
CVE-2026-89488 openvswitch: Fix CT limit teardown use-after-free
CVE-2026-89489 openrisc: fix arbitrary kernel memory access via or1k_atomic syscall
CVE-2026-89500 ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page
CVE-2026-89497 orangefs: skip leading spaces before parsing client debug masks
CVE-2026-89498 orangefs: fix double-free of trailer_buf on readdir copy failure
CVE-2026-89499 ring-buffer: Stop remote reader update when page swap fails
CVE-2026-89496 ocfs2: always run deallocs on copy-on-write completion
CVE-2026-89501 ring-buffer: Hold cpu_buffer::lock when resizing a subbuf

Showing top 20 of 431 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-89736

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