CVE-2026-90198
ALSA: core: Fix use-after-free in snd_card_do_free()
Description
In the Linux kernel, the following vulnerability has been resolved: ALSA: core: Fix use-after-free in snd_card_do_free() A use-after-free was detected in snd_card_do_free() when a sound card managed by devres is unbound while a user-space application still holds an open file descriptor. For managed cards, the memory is allocated using devres_alloc(), and its release function is set to __snd_card_release(), which calls snd_card_free(). When the device is unbound, the unbind thread calls snd_card_free(), which drops a reference to the card's device. If the user thread still has an open file descriptor, the reference count does not reach zero, and the unbind thread blocks on wait_for_completion(&released). When the user thread closes the file descriptor, it drops the final reference, invoking the device release callback release_card_device(), which calls snd_card_do_free(). snd_card_do_free() performs cleanup and calls complete(card->release_completion). This wakes up the unbind thread, which returns from snd_card_free() and __snd_card_release(). The devres core then immediately frees the memory block containing the snd_card structure. Meanwhile, the user thread continues execution in snd_card_do_free() and evaluates `if (!card->managed)`. It reads the `managed` boolean from the snd_card structure that was just freed by the unbind thread, triggering a KASAN use-after-free. Fix this by caching the value of card->managed in a local variable before calling complete(). This ensures that the card pointer is not dereferenced after the unbind thread has been woken up and potentially freed the card. BUG: KASAN: use-after-free in snd_card_do_free sound/core/init.c:604 [inline] BUG: KASAN: use-after-free in release_card_device+0x1ab/0x1b0 sound/core/init.c:153 Read of size 1 at addr ffff8881912ec909 by task syz-executor130/5857 Call Trace: <TASK> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 snd_card_do_free sound/core/init.c:604 [inline] release_card_device+0x1ab/0x1b0 sound/core/init.c:153 device_release+0xc4/0x1f0 drivers/base/core.c:-1 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x222/0x550 lib/kobject.c:737 snd_card_file_remove+0x331/0x390 sound/core/init.c:1125 snd_pcm_release+0x12c/0x160 sound/core/pcm_native.c:2986 __fput+0x418/0xa50 fs/file_table.c:512 fput_close_sync+0x11f/0x240 fs/file_table.c:617 __do_sys_close fs/open.c:1511 [inline] __se_sys_close fs/open.c:1496 [inline] __x64_sys_close+0x7e/0x110 fs/open.c:1496 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK>
INFO
Published Date :
Sept. 17, 2026, 5:17 p.m.
Last Modified :
Sept. 17, 2026, 5:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Cache the value of card->managed locally.
- Complete the release process.
- Ensure the card pointer is not dereferenced after potential freeing.
References to Advisories, Solutions, and Tools
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CVE-2026-90198.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-90198 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-90198
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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CVE-2026-90198 vulnerability anywhere in the article.
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CVE-2026-90198 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 17, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: ALSA: core: Fix use-after-free in snd_card_do_free() A use-after-free was detected in snd_card_do_free() when a sound card managed by devres is unbound while a user-space application still holds an open file descriptor. For managed cards, the memory is allocated using devres_alloc(), and its release function is set to __snd_card_release(), which calls snd_card_free(). When the device is unbound, the unbind thread calls snd_card_free(), which drops a reference to the card's device. If the user thread still has an open file descriptor, the reference count does not reach zero, and the unbind thread blocks on wait_for_completion(&released). When the user thread closes the file descriptor, it drops the final reference, invoking the device release callback release_card_device(), which calls snd_card_do_free(). snd_card_do_free() performs cleanup and calls complete(card->release_completion). This wakes up the unbind thread, which returns from snd_card_free() and __snd_card_release(). The devres core then immediately frees the memory block containing the snd_card structure. Meanwhile, the user thread continues execution in snd_card_do_free() and evaluates `if (!card->managed)`. It reads the `managed` boolean from the snd_card structure that was just freed by the unbind thread, triggering a KASAN use-after-free. Fix this by caching the value of card->managed in a local variable before calling complete(). This ensures that the card pointer is not dereferenced after the unbind thread has been woken up and potentially freed the card. BUG: KASAN: use-after-free in snd_card_do_free sound/core/init.c:604 [inline] BUG: KASAN: use-after-free in release_card_device+0x1ab/0x1b0 sound/core/init.c:153 Read of size 1 at addr ffff8881912ec909 by task syz-executor130/5857 Call Trace: <TASK> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 snd_card_do_free sound/core/init.c:604 [inline] release_card_device+0x1ab/0x1b0 sound/core/init.c:153 device_release+0xc4/0x1f0 drivers/base/core.c:-1 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x222/0x550 lib/kobject.c:737 snd_card_file_remove+0x331/0x390 sound/core/init.c:1125 snd_pcm_release+0x12c/0x160 sound/core/pcm_native.c:2986 __fput+0x418/0xa50 fs/file_table.c:512 fput_close_sync+0x11f/0x240 fs/file_table.c:617 __do_sys_close fs/open.c:1511 [inline] __se_sys_close fs/open.c:1496 [inline] __x64_sys_close+0x7e/0x110 fs/open.c:1496 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/90xxx/CVE-2026-90198.json">CVE-2026-90198</a> Added Reference https://git.kernel.org/stable/c/03c5dabc8f16bc212a5b26d2425c03a55e55a86d Added Reference https://git.kernel.org/stable/c/09b27dd01b98480334c10bf6fb8d41d5fb063a4b Added Reference https://git.kernel.org/stable/c/5ae1a690c522fea2900ff56c8c2ace7b059f5e04 Added Reference https://git.kernel.org/stable/c/6da22efb5cf490b06ffbca32b10fc8af7654fee0 Added Reference https://git.kernel.org/stable/c/7d9b5e86775fa97a487da08b9aa76e1674bf8868 Added Reference https://git.kernel.org/stable/c/a561012868ae37c28f61fdf658bf6f251bc0e8e8 Added Reference https://git.kernel.org/stable/c/d3d67f680dbc23a5e5e3d3ecfdbf700465809877