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

Summary

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.

Timeline

1. Sep 11, 2026, 7:47 PM UTCCVE published
2. Oct 19, 2026, 8:52 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 6d4b937251386d9c6f968e7802f0cb16a8523772; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 4ea70146ab9376092297eb8b622ef1792797f2cf; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in a17b345daff46fec4af9f1ecbdf350208016dd15; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in bdfda99c5763822a9a888e8af0ad7d9312ffcfe2; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 4c66719dd1e4023c5e3f7d050f1bbefec3dfbeb4; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 2bf5e8f7c9bf4ad3be343a9a6e3e50a34264d25e; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 00ef529a5402f41eb1d227916437e237450719f9; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 18c7d85864e554adc8fad1e8d2e9d2cb6c3911c8

• Linux Linux

  2.6.12

• KernelLinux

  From 2.6.12 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.109; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4

References 8