CVE-2026-31438 PUBLISHED

netfs: Fix kernel BUG in netfs_limit_iter() for ITER_KVEC iterators

Assigner: Linux
Reserved: 09.03.2026 Published: 22.04.2026 Updated: 22.04.2026

In the Linux kernel, the following vulnerability has been resolved:

netfs: Fix kernel BUG in netfs_limit_iter() for ITER_KVEC iterators

When a process crashes and the kernel writes a core dump to a 9P filesystem, __kernel_write() creates an ITER_KVEC iterator. This iterator reaches netfs_limit_iter() via netfs_unbuffered_write(), which only handles ITER_FOLIOQ, ITER_BVEC and ITER_XARRAY iterator types, hitting the BUG() for any other type.

Fix this by adding netfs_limit_kvec() following the same pattern as netfs_limit_bvec(), since both kvec and bvec are simple segment arrays with pointer and length fields. Dispatch it from netfs_limit_iter() when the iterator type is ITER_KVEC.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from cae932d3aee55035a54415dcea8e7ecf2ec469b5 to 18c2e20b42dd21db599e42d05ddaeeb647b2bb6d (excl.)
  • affected from cae932d3aee55035a54415dcea8e7ecf2ec469b5 to 4bc2d72c7695cedf6d4e1a558924903c2b28a78e (excl.)
  • affected from cae932d3aee55035a54415dcea8e7ecf2ec469b5 to 00d6df7115f6972370974212de9088087820802e (excl.)
  • affected from cae932d3aee55035a54415dcea8e7ecf2ec469b5 to 67e467a11f62ff64ad219dc6aa5459e132c79d14 (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 6.8 is affected
  • unaffected from 0 to 6.8 (excl.)
  • unaffected from 6.12.80 to 6.12.* (incl.)
  • unaffected from 6.18.21 to 6.18.* (incl.)
  • unaffected from 6.19.11 to 6.19.* (incl.)
  • unaffected from 7.0 to * (incl.)

References