CVE-2026-89765

/// Technical 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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References