Описание
In the Linux kernel, the following vulnerability has been resolved:
ALSA: timer: Fix UAF at snd_timer_user_params()
At releasing a timer object, e.g. when a userspace timer
(CONFIG_SND_UTIMER) gets closed and snd_timer_free() is called, it
tries to detach the timer instances and release the resources.
However, it's still possible that other in-flight tasks are holding
the timer instance where the to-be-deleted timer object is associated,
and this may lead to racy accesses.
Fortunately, most of ioctls dealing with the timer instance list
already have the protection with register_mutex, and this also avoids
such races. But, SNDRV_TIMER_IOCTL_PARAMS isn't protected, hence the
concurrent ioctl may lead to use-after-free.
This patch just adds the guard with register_mutex to protect
snd_timer_user_params() for covering the code path as a quick
workaround. It's no hot-path but rather a rarely issued ioctl, so the
performance penalty doesn't matter.
A flaw was found in the Linux kernel's Advanced Linux Sound Architecture (ALSA) timer component. A race condition can occur during the release of a timer object, specifically when the SNDRV_TIMER_IOCTL_PARAMS ioctl is called concurrently. This can lead to a use-after-free vulnerability, potentially allowing a local attacker to achieve arbitrary code execution or cause a denial of service.
Отчет
ALSA timer has a local race based use after free in snd_timer_user_params() because SNDRV_TIMER_IOCTL_PARAMS was not protected by register_mutex while timer teardown can detach and free the timer object. A local process that can open the ALSA timer device can race this ioctl with closing or releasing a userspace timer and can reach stale timer instance state. For the CVSS the PR:L is used because reliable triggering requires local code execution and access to the ALSA timer interface, but it does not require full administrator privileges in common desktop or audio group configurations. The issue is not network reachable.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 10 | kernel | Fixed | RHSA-2026:68507 | 17.09.2026 |
| Red Hat Enterprise Linux 8 | kernel-rt | Fixed | RHSA-2026:68532 | 17.09.2026 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2026:68531 | 17.09.2026 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2026:68570 | 17.09.2026 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2026:68570 | 17.09.2026 |
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Дополнительная информация
Статус:
EPSS
4.7 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: Fix UAF at snd_timer_user_params() At releasing a timer object, e.g. when a userspace timer (CONFIG_SND_UTIMER) gets closed and snd_timer_free() is called, it tries to detach the timer instances and release the resources. However, it's still possible that other in-flight tasks are holding the timer instance where the to-be-deleted timer object is associated, and this may lead to racy accesses. Fortunately, most of ioctls dealing with the timer instance list already have the protection with register_mutex, and this also avoids such races. But, SNDRV_TIMER_IOCTL_PARAMS isn't protected, hence the concurrent ioctl may lead to use-after-free. This patch just adds the guard with register_mutex to protect snd_timer_user_params() for covering the code path as a quick workaround. It's no hot-path but rather a rarely issued ioctl, so the performance penalty doesn't matter.
In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: Fix UAF at snd_timer_user_params() At releasing a timer object, e.g. when a userspace timer (CONFIG_SND_UTIMER) gets closed and snd_timer_free() is called, it tries to detach the timer instances and release the resources. However, it's still possible that other in-flight tasks are holding the timer instance where the to-be-deleted timer object is associated, and this may lead to racy accesses. Fortunately, most of ioctls dealing with the timer instance list already have the protection with register_mutex, and this also avoids such races. But, SNDRV_TIMER_IOCTL_PARAMS isn't protected, hence the concurrent ioctl may lead to use-after-free. This patch just adds the guard with register_mutex to protect snd_timer_user_params() for covering the code path as a quick workaround. It's no hot-path but rather a rarely issued ioctl, so the performance penalty doesn't matter.
In the Linux kernel, the following vulnerability has been resolved: A ...
EPSS
4.7 Medium
CVSS3