CVE-2026-53241
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk7th percentile — higher than 7% of all known CVEs
Summary
In the Linux kernel, a vulnerability in the ALSA seq: dummy driver causes a stack overread when handling UMP events. The dummy sequencer copies events into a legacy-sized stack temporary that is smaller than struct snd_seq_ump_event, leading to out-of-bounds read.
Risk Assessment
The vulnerability may lead to kernel memory information disclosure or system panic due to stack overread. The risk is significant in environments using UMP events in the ALSA sequencer.
Recommendation
Immediately update the Linux kernel to a version containing the fix (commit resolving the issue). Monitor official security advisories from your Linux distribution.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: dummy: fix UMP event stack overread The dummy sequencer port forwards events by copying an incoming struct snd_seq_event into a stack temporary, rewriting source and destination, and dispatching the temporary to subscribers. That legacy event storage is smaller than struct snd_seq_ump_event. When a UMP event reaches the dummy client, the copy leaves the UMP flag set but only provides legacy-sized stack storage. The subscriber delivery path then uses snd_seq_event_packet_size() and copies a UMP-sized packet from that stack object, reading past the end of the temporary. Use the existing union __snd_seq_event storage and copy the packet size reported for the incoming event before rewriting the common routing fields. This preserves the full UMP packet for UMP events while keeping legacy event handling unchanged.