CVE-2026-98266ALSA: core: Fix potential UAF after asynchronous card release

Official description

In the Linux kernel, the following vulnerability has been resolved: ALSA: core: Fix potential UAF after asynchronous card release Usually a sound driver releases the resources assigned to the card via snd_card_free(), and it synchronizes with the whole release procedure. However, when the card is released asynchronously via snd_card_free_when_closed() like USB-audio driver, the situation is slightly different; although the snd_card_disconnect() call at the disconnection guarantees that any newer accesses will be gated, the in-flight tasks might be still accessing to the underlying card->dev device even after the disconnection, which would cause a use-after-free in the end, as reported by fuzzers. For addressing the bug above, this patch takes the refcount of card->dev at initialization of the card object, and releases at its destructor. This assures the availability of the card->dev in its whole lifecycle.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/5c0df40aa577e405c458e44e8d458dd78407f4af
• https://git.kernel.org/stable/c/2dec4642589a663e064e4411d92d6e8fa250d53b
• https://git.kernel.org/stable/c/398b21608955c9712a012355b69a39407367edc9
• https://git.kernel.org/stable/c/fd95e68df6fe66344161a1329cbe5e5805e7b704