ALSA: core: Fix potential UAF after asynchronous card release

Summary

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.

Timeline

1. Oct 6, 2026, 8:45 AM UTCCVE published
2. Oct 19, 2026, 9:16 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 5c0df40aa577e405c458e44e8d458dd78407f4af; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 2dec4642589a663e064e4411d92d6e8fa250d53b; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 398b21608955c9712a012355b69a39407367edc9; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in fd95e68df6fe66344161a1329cbe5e5805e7b704

• Linux Linux

  2.6.12

• KernelLinux

  From 2.6.12 · fixed in 6.12.112; From 6.13.0 · fixed in 6.18.54; From 6.19.0 · fixed in 7.2.8

References 4