CVE-2026-53193

CVE-2026-53193 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: Forcibly close timer instances at closing When snd_timer object is freed via snd_timer_free() and still pending snd_timer_instance objects are assigned to the timer object, it tries to unlink all instances and just set NULL to each ti->timer, then releases the resources immediately. The problem is, however, when there are slave timer instances that are associated with a master instance linked to this timer: namely, those slave instances still point to the freed timer object although the master instance is unlinked, which may lead to user-after-free. The bug can be easily triggered particularly when a new userspace-driven timers (CONFIG_SND_UTIMER) is involved, since it can create and delete the timer object via a simple file open/close, while the other applications may keep accessing to that timer. This patch is an attempt to paper over the problem above: now instead of just unlinking, call snd_timer_close[_locked]() forcibly for each pending timer instance, so that all assigned slave timer instances are properly detached, too. Since snd_timer_close() might be called later by the driver that created that instance, the check of SNDRV_TIMER_IFLG_DEAD is added at the beginning, too.

Frequently asked questions

What is CVE-2026-53193?
In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: Forcibly close timer instances at closing When snd_timer object is freed via snd_timer_free() and still pending snd_timer_instance objects are assigned to the timer object, it tries to unlink all instances and just set NULL to each ti->timer, then releases the resources immediately. The problem is, however, when there are slave timer instances that are associated with a master instance linked to this timer: namely, those slave instances still point to the freed timer object although the master instance is unlinked, which may lead to user-after-free. The bug can be easily triggered particularly when a new userspace-driven timers (CONFIG_SND_UTIMER) is involved, since it can create and delete the timer object via a simple file open/close, while the other applications may keep accessing to that timer. This patch is an attempt to paper over the problem above: now instead of just unlinking, call snd_timer_close[_locked]() forcibly for each pending timer instance, so that all assigned slave timer instances are properly detached, too. Since snd_timer_close() might be called later by the driver that created that instance, the check of SNDRV_TIMER_IFLG_DEAD is added at the beginning, too.
How severe is CVE-2026-53193?
CVE-2026-53193 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-53193 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-53193?
CVE-2026-53193 primarily affects Linux Linux Kernel. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-53193?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-53193 have an EU (EUVD) identifier?
Yes. CVE-2026-53193 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39284.
When was CVE-2026-53193 published?
CVE-2026-53193 was published on 2026-06-25 and last updated on 2026-07-06.

References

Affected products (8)

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