{"id":"AZL-102738","summary":"CVE-2026-90198 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: core: Fix use-after-free in snd_card_do_free()\n\nA use-after-free was detected in snd_card_do_free() when a sound card\nmanaged by devres is unbound while a user-space application still holds an\nopen file descriptor.\n\nFor managed cards, the memory is allocated using devres_alloc(), and its\nrelease function is set to __snd_card_release(), which calls\nsnd_card_free(). When the device is unbound, the unbind thread calls\nsnd_card_free(), which drops a reference to the card's device. If the user\nthread still has an open file descriptor, the reference count does not\nreach zero, and the unbind thread blocks on wait_for_completion(&released).\n\nWhen the user thread closes the file descriptor, it drops the final\nreference, invoking the device release callback release_card_device(),\nwhich calls snd_card_do_free(). snd_card_do_free() performs cleanup and\ncalls complete(card-\u003erelease_completion). This wakes up the unbind thread,\nwhich returns from snd_card_free() and __snd_card_release(). The devres\ncore then immediately frees the memory block containing the snd_card\nstructure.\n\nMeanwhile, the user thread continues execution in snd_card_do_free() and\nevaluates `if (!card-\u003emanaged)`. It reads the `managed` boolean from the\nsnd_card structure that was just freed by the unbind thread, triggering a\nKASAN use-after-free.\n\nFix this by caching the value of card-\u003emanaged in a local variable before\ncalling complete(). This ensures that the card pointer is not dereferenced\nafter the unbind thread has been woken up and potentially freed the card.\n\nBUG: KASAN: use-after-free in snd_card_do_free sound/core/init.c:604\n[inline]\nBUG: KASAN: use-after-free in release_card_device+0x1ab/0x1b0\nsound/core/init.c:153\nRead of size 1 at addr ffff8881912ec909 by task syz-executor130/5857\n\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120\n print_address_description+0x55/0x1e0 mm/kasan/report.c:378\n print_report+0x58/0x70 mm/kasan/report.c:482\n kasan_report+0x117/0x150 mm/kasan/report.c:595\n snd_card_do_free sound/core/init.c:604 [inline]\n release_card_device+0x1ab/0x1b0 sound/core/init.c:153\n device_release+0xc4/0x1f0 drivers/base/core.c:-1\n kobject_cleanup lib/kobject.c:689 [inline]\n kobject_release lib/kobject.c:720 [inline]\n kref_put include/linux/kref.h:65 [inline]\n kobject_put+0x222/0x550 lib/kobject.c:737\n snd_card_file_remove+0x331/0x390 sound/core/init.c:1125\n snd_pcm_release+0x12c/0x160 sound/core/pcm_native.c:2986\n __fput+0x418/0xa50 fs/file_table.c:512\n fput_close_sync+0x11f/0x240 fs/file_table.c:617\n __do_sys_close fs/open.c:1511 [inline]\n __se_sys_close fs/open.c:1496 [inline]\n __x64_sys_close+0x7e/0x110 fs/open.c:1496\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n \u003c/TASK\u003e","modified":"2026-09-18T14:17:50.656131569Z","published":"2026-09-17T17:17:14Z","upstream":["CVE-2026-90198"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90198"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-102738.json"}}],"schema_version":"1.9.0"}