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Vulnerability Change Records for CVE-2026-64398

Change History

New CVE Received from kernel.org 7/25/2026 6:17:23 AM

Action Type Old Value New Value
Added Description

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

ksmbd: add a permission check for FSCTL_SET_ZERO_DATA

FSCTL_SET_ZERO_DATA in smb2_ioctl() destroys file data via
ksmbd_vfs_zero_data() -> vfs_fallocate(PUNCH_HOLE/ZERO_RANGE) after
checking only the share-level KSMBD_TREE_CONN_FLAG_WRITABLE, with no
per-handle access check. A handle opened with only FILE_WRITE_ATTRIBUTES
still yields an FMODE_WRITE filp (FILE_WRITE_ATTRIBUTES is part of
FILE_WRITE_DESIRE_ACCESS_LE, so smb2_create_open_flags() opens it
O_WRONLY), so the vfs_fallocate FMODE_WRITE check does not stop it; only
the missing fp->daccess gate would. Reproduced on mainline 7.1-rc7 with
KASAN by an authenticated SMB client: a FILE_WRITE_ATTRIBUTES-only handle
zeroed 4096 bytes of file data it had no FILE_WRITE_DATA right to
(6/6; a FILE_READ_DATA-only handle was correctly denied).

This is the unfixed sibling of commit cc57232cae23 ("ksmbd: fix FSCTL
permission bypass by adding a permission check for FSCTL_SET_SPARSE").
Because SET_ZERO_DATA writes data (not an attribute), require
FILE_WRITE_DATA.
Added Reference

                  
                
              
https://git.kernel.org/stable/c/25377f369688dd0bd814dc8965ed26d44238ecaa
Added Reference

                  
                
              
https://git.kernel.org/stable/c/3072d82461f498c85daea8766e9d8bfbada31605
Added Reference

                  
                
              
https://git.kernel.org/stable/c/3320ba068198adc144c89d6661b805acce01735b
Added Reference

                  
                
              
https://git.kernel.org/stable/c/57f2042fd87d7ce8fc3ac8b6c176e554df68b1a7
Added Reference

                  
                
              
https://git.kernel.org/stable/c/ca53bb17f4e8232cfaece3953d3cef62c559b039
Added Reference

                  
                
              
https://git.kernel.org/stable/c/deffa929086d7902e30918adf3dd27ccfe9c08b1
Added Affected

                  
                
              
[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","programFiles":["fs/smb/server/smb2pdu.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"25377f369688dd0bd814dc8965ed26d44238ecaa","versionType":"git","status":"affected"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"3072d82461f498c85daea8766e9d8bfbada31605","versionType":"git","status":"affected"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"ca53bb17f4e8232cfaece3953d3cef62c559b039","versionType":"git","status":"affected"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"57f2042fd87d7ce8fc3ac8b6c176e554df68b1a7","versionType":"git","status":"affected"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"deffa929086d7902e30918adf3dd27ccfe9c08b1","versionType":"git","status":"affected"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"3320ba068198adc144c89d6661b805acce01735b","versionType":"git","status":"affected"},{"version":"0","lessThan":"6.1.178","versionType":"semver","status":"affected"},{"version":"0","lessThan":"6.6.145","versionType":"semver","status":"affected"},{"version":"0","lessThan":"6.12.96","versionType":"semver","status":"affected"},{"version":"0","lessThan":"6.18.39","versionType":"semver","status":"affected"},{"version":"0","lessThan":"7.1.4","versionType":"semver","status":"affected"}]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","programFiles":["fs/smb/server/smb2pdu.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","versions":[{"version":"6.1.178","lessThanOrEqual":"6.1.*","versionType":"semver","status":"unaffected"},{"version":"6.6.145","lessThanOrEqual":"6.6.*","versionType":"semver","status":"unaffected"},{"version":"6.12.96","lessThanOrEqual":"6.12.*","versionType":"semver","status":"unaffected"},{"version":"6.18.39","lessThanOrEqual":"6.18.*","versionType":"semver","status":"unaffected"},{"version":"7.1.4","lessThanOrEqual":"7.1.*","versionType":"semver","status":"unaffected"},{"version":"7.2-rc1","lessThanOrEqual":"*","versionType":"original_commit_for_fix","status":"unaffected"}]}]