CPU hang via overflowing timer resolution product
Published Aug 15, 2026 · Updated Aug 15, 2026
Divide by zero in the Linux kernel ALSA sequencer allows local users to hang a CPU through a crafted userspace timer. initialize_timer() multiplies the attacker-controlled 64-bit resolution by the update frequency without detecting overflow, then divides by the wrapped product, which can be zero. Reachability requires unprivileged access to /dev/snd/timer and /dev/snd/seq; the fault occurs with interrupts disabled and leaves tmr->lock held.
Summary
What happened
Divide by zero in the Linux kernel ALSA sequencer allows local users to hang a CPU through a crafted userspace timer. initialize_timer() multiplies the attacker-controlled 64-bit resolution by the update frequency without detecting overflow, then divides by the wrapped product, which can be zero. Reachability requires unprivileged access to /dev/snd/timer and /dev/snd/seq; the fault occurs with interrupts disabled and leaves tmr->lock held.
The record
- CVE
- CVE-2026-74504
- Published
- Aug 15, 2026
- Updated
- Aug 15, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-369, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 15, 2026CVE publishedPublication date reported by the CVE source.
- Aug 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=37745918e0e7575bc40f38da93a99b9fa6406224 <21e19688433452dfbbbe6b2bb670dea6eb92f0f6
- Affected versionversion=37745918e0e7575bc40f38da93a99b9fa6406224 <42c6543ff27ea280334244458d4f52ec7133cc05
- Affected versionversion=37745918e0e7575bc40f38da93a99b9fa6406224 <5260e195c53e898a4a76527d4bb2178f31795e78
- Affected versionversion=37745918e0e7575bc40f38da93a99b9fa6406224 <d0e19932875746118e298b4c974f3b2d4aeb16fc
- Affected versionversion=6.12
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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