CVE-2026-98685smb: client: discard post-EOF pagecache when extending a file via clone range

Official description

In the Linux kernel, the following vulnerability has been resolved: smb: client: discard post-EOF pagecache when extending a file via clone range cifs_remap_file_range() discarded the pagecache only for the folios overlapping the destination region, so when a clone extends the file the folio straddling the old EOF - which may hold data dirtied past EOF through an mmap - was never dropped and became visible as file content once the file was extended. Start the discard at the smaller of fstart and the old EOF. i_size is still old here, so nothing past the old EOF is flushed to the server.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/15bb9f1d3e967e328649e92a1451e60a0dc66118
• https://git.kernel.org/stable/c/4721587f96cb8de8164f3fd203093a0875560999