SB2026081574 - Use-after-free in Linux kernel seq oss

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-74388)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in the ALSA OSS sequencer event handling logic when processing SysEx data embedded in MIDI events and dispatching a pending event after a sequencer port is closed concurrently. A local user can send crafted MIDI bytes that produce a pending SysEx event with a stale pointer to cause a denial of service.

The issue occurs during concurrent port closure before deferred event dispatch.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/6dc781778b595be94c31395b2cb167f65145d91f
• https://git.kernel.org/stable/c/7aad70cabd8f34cf11a9593fcd3f2ac3f5496943
• https://git.kernel.org/stable/c/7c349b4f2a603202fb8c363bd2774a22ac2fddf3