CVE-2026-74504

CVE Details

Release Date:	2026-08-15
Impact:	Low	What is this?

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Fix division by zero in initialize_timer() A userspace-driven ALSA timer (SND_UTIMER) lets an unprivileged user set the backing snd_timer's hardware resolution to an arbitrary 64-bit value via SNDRV_TIMER_IOCTL_CREATE. snd_utimer_create() only rejects zero. When such a timer is bound to a sequencer queue, initialize_timer() computes the tick period as tmr->ticks = 1000000000 / (r * freq); where r is that user-controlled resolution and freq is the sequencer update rate in Hz, clamped to MIN_FREQUENCY..MAX_FREQUENCY (10..6250). A resolution of 2^63 makes the 64-bit product r * freq wrap to zero for any even freq, including DEFAULT_FREQUENCY (1000), so the division faults with a divide-by-zero. The division runs under tmr->lock with interrupts disabled, so the oops leaves the spinlock held and hangs the CPU. It is reachable by an unprivileged user with access to /dev/snd/timer and /dev/snd/seq. Oops: divide error: 0000 [#1] SMP KASAN PTI CPU: 7 UID: 1000 PID: 456 Comm: alsa_seq_utimer Not tainted 7.2.0-rc4+ RIP: 0010:initialize_timer.constprop.0+0x20a/0x2d0 snd_seq_timer_start+0x15e/0x2b0 snd_seq_control_queue+0x56f/0xba0 snd_seq_write+0x3e0/0x730 Reject an overflowing product with check_mul_overflow() and fall back to a single tick, which also avoids feeding a wrapped-but-nonzero divisor (e.g. 2^63 * 1000 mod 2^64 == 0, or other resolutions wrapping to a small value) into the period computation.

See more information about CVE-2026-74504 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	5.5
Vector String:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Version:	3.1
Attack Vector:	Local
Attack Complexity:	Low
Privileges Required:	Low
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	None
Integrity Impact:	None
Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 10 (kernel-uek)	ELSA-2026-500248	2026-09-04
Oracle Linux version 9 (kernel-uek)	ELSA-2026-500248	2026-09-04