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CVE-2026-74504

UnknownEPSS 0.17%

Last modified

CVE-2026-74504 is a vulnerability of currently unknown severity. 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. EPSS estimates a 0.17% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.17%

6.5th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 37745918e0e7575bc40f38da93a99b9fa6406224, < d0e19932875746118e298b4c974f3b2d4aeb16fc; >= 37745918e0e7575bc40f38da93a99b9fa6406224, < 5260e195c53e898a4a76527d4bb2178f31795e78; >= 37745918e0e7575bc40f38da93a99b9fa6406224, < 42c6543ff27ea280334244458d4f52ec7133cc05; >= 37745918e0e7575bc40f38da93a99b9fa6406224, < 21e19688433452dfbbbe6b2bb670dea6eb92f0f6
LinuxLinux6.12

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-74504?
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.
How severe is CVE-2026-74504?
Severity scoring for CVE-2026-74504 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.
How do I fix CVE-2026-74504?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST