What’s Vulnerable › Vulnerabilities

CVE-2026-89765: timers/itimer: Zero-init old itimerval before copy to userspace

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-11 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: timers/itimer: Zero-init old itimerval before copy to userspace On native sparc64, struct __kernel_old_timeval contains a four-byte hole after tv_usec because tv_sec is 64-bit while __kernel_suseconds_t is 32-bit. put_itimerval() fills only the named fields in a stack-allocated __kernel_old_itimerval and copies the entire object to userspace, so getitimer() can expose the two padding holes. Zero-initialize the aggregate before assigning the fields so implicit padding is deterministic before it crosses the user/kernel boundary.

Affected products

• Linux kernel: 2.6.12 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/00ef529a5402f41eb1d227916437e237450719f9
• https://git.kernel.org/stable/c/18c7d85864e554adc8fad1e8d2e9d2cb6c3911c8
• https://git.kernel.org/stable/c/2bf5e8f7c9bf4ad3be343a9a6e3e50a34264d25e
• https://git.kernel.org/stable/c/4c66719dd1e4023c5e3f7d050f1bbefec3dfbeb4
• https://git.kernel.org/stable/c/4ea70146ab9376092297eb8b622ef1792797f2cf
• https://git.kernel.org/stable/c/6d4b937251386d9c6f968e7802f0cb16a8523772
• https://git.kernel.org/stable/c/a17b345daff46fec4af9f1ecbdf350208016dd15
• https://git.kernel.org/stable/c/bdfda99c5763822a9a888e8af0ad7d9312ffcfe2

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