CVE-2026-31438

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxcae932d3aee55035a54415dcea8e7ecf2ec469b5 < 18c2e20b42dd21db599e42d05ddaeeb647b2bb6daffected
LinuxLinuxcae932d3aee55035a54415dcea8e7ecf2ec469b5 < 4bc2d72c7695cedf6d4e1a558924903c2b28a78eaffected
LinuxLinuxcae932d3aee55035a54415dcea8e7ecf2ec469b5 < 00d6df7115f6972370974212de9088087820802eaffected
LinuxLinuxcae932d3aee55035a54415dcea8e7ecf2ec469b5 < 67e467a11f62ff64ad219dc6aa5459e132c79d14affected
LinuxLinux6.8affected
LinuxLinux0 < 6.8unaffected
LinuxLinux6.12.80 <= 6.12.*unaffected
LinuxLinux6.18.21 <= 6.18.*unaffected
LinuxLinux6.19.11 <= 6.19.*unaffected
LinuxLinux7.0 <= *unaffected

Weaknesses

References