CVE Catalog

CVE-2026-98314

Low risk· EPSS 8%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.18%

8th percentile - higher than 8% of all known CVEs

Summary

In the Linux kernel ALSA subsystem, snd_pcm_timer_init() registered the PCM timer before setting timer->private_data. During a brief window, a concurrent reader could reach the timer via /proc/asound/timers or snd_timer_open() and invoke callbacks that dereference a NULL pointer. The fix moves the private_data assignment before registration.

Risk Assessment

A NULL-pointer dereference in the kernel can cause a system panic and denial of service. The risk occurs with concurrent access to PCM timers, e.g. via /proc/asound/timers.

Recommendation

Update the Linux kernel to a patched version. If updating is not possible, limit concurrent access to sound devices and /proc/asound files.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: set timer->private_data before registering the PCM timer snd_pcm_timer_init() calls snd_device_register() to link the new struct snd_timer into the global timer list while it still carries hw.c_resolution = snd_pcm_timer_resolution (and hw.start/hw.stop), and only afterwards sets timer->private_data = substream. Once the timer is on the list under register_mutex, a concurrent reader can already reach it through the same mutex and invoke these callbacks. /proc/asound/timers does this via c_resolution(), and snd_timer_open()+snd_timer_start() reach start()/stop() the same way. All three dereference timer->private_data, which for this brief window is NULL, giving a NULL-pointer dereference: substream = timer->private_data; return substream->runtime ? ... // substream is NULL Move the private_data/private_free assignment before snd_device_register() so the timer is never visible on the list without its private_data set. On the snd_device_register() failure path, private_free() (snd_pcm_timer_free()) can now run, but it only does substream->timer = NULL, which is already NULL at that point since substream->timer is set to the new timer just once, after a successful registration -- so the failure path stays safe.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS