CVE-2026-89736

usb: gadget: u_audio: Fix use-after-free on sound card disconnect

State: Published
Severity: 7.8 High
Published: Sep 11, 2026
Updated: Oct 19, 2026
Reserved: Sep 11, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	33f341c1fc60e172a3515c51bdabee11e83d1ee9 to before a7ecd1a04f4f485d7be6443d0f0b2c61a800cb82Affected b131989797f7287d7fdadb2bababc05a15d44750 to before f983793f03148b097977f200298db215cd2d4438Affected 3bc7324e4911351e39c54a62e6ca46321cb10faf to before 6f46762196f04464e1050a9ee94e72b917db9010Affected 6c67ed9ad9b83e453e808f9b31a931a20a25629b to before 891a8d11f4d5eb50b2ce7570f4f98204a7a57493Affected 6c67ed9ad9b83e453e808f9b31a931a20a25629b to before c74ff0b1a0fca53d3ac185873c87d6a719b30a47Affected 6c67ed9ad9b83e453e808f9b31a931a20a25629b to before 4e747c864a88537e18b1ffc19a1954c9686bb8e1Affected 6c67ed9ad9b83e453e808f9b31a931a20a25629b to before 79a92896e2bb9471550c56fc23d8d93592f04c27Affected 6c67ed9ad9b83e453e808f9b31a931a20a25629b to before 858965947081d10d41d9a1010a540d3d5eea958bAffected 3e016ef2e72da93a2ea7afbb45de1b481b44d761Affected 3256e152b645fc1e788ba44c2d8ced690113e3e6Affected 0eda2004f38d95ef5715d62be884cd344260535bAffected 43ca70753dfffd517d2af126da28690f8f615605Affected 5.10.177 to before 5.10.270Affected 5.15.105 to before 5.15.221Affected 6.1.22 to before 6.1.188Affected 4.14.312 to before 4.15Affected 4.19.280 to before 4.20Affected 5.4.240 to before 5.5Affected 6.2.9 to before 6.3Affected
LinuxLinux	6.3Affected before 6.3Not affected 5.10.270 through 5.10.Not affected 5.15.221 through 5.15.Not affected 6.1.188 through 6.1.Not affected 6.6.157 through 6.6.Not affected 6.12.109 through 6.12.Not affected 6.18.50 through 6.18.Not affected 7.2.4 through 7.2.*Not affected 7.3 and laterNot affected

Product

Versions

LinuxLinux

33f341c1fc60e172a3515c51bdabee11e83d1ee9 to before a7ecd1a04f4f485d7be6443d0f0b2c61a800cb82Affected
b131989797f7287d7fdadb2bababc05a15d44750 to before f983793f03148b097977f200298db215cd2d4438Affected
3bc7324e4911351e39c54a62e6ca46321cb10faf to before 6f46762196f04464e1050a9ee94e72b917db9010Affected
6c67ed9ad9b83e453e808f9b31a931a20a25629b to before 891a8d11f4d5eb50b2ce7570f4f98204a7a57493Affected
6c67ed9ad9b83e453e808f9b31a931a20a25629b to before c74ff0b1a0fca53d3ac185873c87d6a719b30a47Affected
6c67ed9ad9b83e453e808f9b31a931a20a25629b to before 4e747c864a88537e18b1ffc19a1954c9686bb8e1Affected
6c67ed9ad9b83e453e808f9b31a931a20a25629b to before 79a92896e2bb9471550c56fc23d8d93592f04c27Affected
6c67ed9ad9b83e453e808f9b31a931a20a25629b to before 858965947081d10d41d9a1010a540d3d5eea958bAffected
3e016ef2e72da93a2ea7afbb45de1b481b44d761Affected
3256e152b645fc1e788ba44c2d8ced690113e3e6Affected
0eda2004f38d95ef5715d62be884cd344260535bAffected
43ca70753dfffd517d2af126da28690f8f615605Affected
5.10.177 to before 5.10.270Affected
5.15.105 to before 5.15.221Affected
6.1.22 to before 6.1.188Affected
4.14.312 to before 4.15Affected
4.19.280 to before 4.20Affected
5.4.240 to before 5.5Affected
6.2.9 to before 6.3Affected

LinuxLinux

6.3Affected
before 6.3Not affected
5.10.270 through 5.10.*Not affected
5.15.221 through 5.15.*Not affected
6.1.188 through 6.1.*Not affected
6.6.157 through 6.6.*Not affected
6.12.109 through 6.12.*Not affected
6.18.50 through 6.18.*Not affected
7.2.4 through 7.2.*Not affected
7.3 and laterNot affected

References

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