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CVE-2026-64159 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix zeropoint update where i_size > remote_i_size Fix the update of the zero point[*] by netfs_release_folio() when there is uncommitted data in the pagecache beyond the folio being released but the on-server EOF is in this folio (ie. i_size > remote_i_size). The update needs to limit zero_point to remote_i_size, not i_size as i_size is a local phenomenon reflecting updates made locally to the pagecache, not stuff written to the server. remote_i_size tracks the server's i_size. [*] The zero point is the file position from which we can assume that the server will just return zeros, so we can avoid generating reads. Note that netfs_invalidate_folio() probably doesn't need fixing as zero_point should be updated by setattr after truncation or fallocate. Found with: fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \ /xfstest.test/junk --replay-ops=junk.fsxops using the following as junk.fsxops: truncate 0x0 0x1bbae 0x82864 write 0x3ef2e 0xf9c8 0x1bbae write 0x67e05 0xcb5a 0x4e8f6 mapread 0x57781 0x85b6 0x7495f copy_range 0x5d3d 0x10329 0x54fac 0x7495f write 0x64710 0x1c2b 0x7495f mapread 0x64000 0x1000 0x7495f on cifs with the default cache option. It shows read-gaps on folio 0x64 failing with a short read (ie. it hits EOF) if the FMODE_READ check is commented out in netfs_perform_write(): if (//(file->f_mode & FMODE_READ) || netfs_is_cache_enabled(ctx)) { and no fscache. This was initially found with the generic/522 xfstest.


Metrics

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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
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URL Source(s) Tag(s)
kernel.org
kernel.org

Weakness Enumeration

CWE-ID CWE Name Source

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-64159
NVD Published Date:
07/19/2026
NVD Last Modified:
07/19/2026
Source:
kernel.org