GHSA-HRH3-6X34-5FXF
Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-19 18:31In 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.
{
"affected": [],
"aliases": [
"CVE-2026-64159"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-19T16:17:57Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix zeropoint update where i_size \u003e remote_i_size\n\nFix the update of the zero point[*] by netfs_release_folio() when there is\nuncommitted data in the pagecache beyond the folio being released but the\non-server EOF is in this folio (ie. i_size \u003e remote_i_size). The update\nneeds to limit zero_point to remote_i_size, not i_size as i_size is a local\nphenomenon reflecting updates made locally to the pagecache, not stuff\nwritten to the server. remote_i_size tracks the server\u0027s i_size.\n\n[*] The zero point is the file position from which we can assume that the\n server will just return zeros, so we can avoid generating reads.\n\nNote that netfs_invalidate_folio() probably doesn\u0027t need fixing as\nzero_point should be updated by setattr after truncation or fallocate.\n\nFound with:\n\n fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \\\n /xfstest.test/junk --replay-ops=junk.fsxops\n\nusing the following as junk.fsxops:\n\n truncate 0x0 0x1bbae 0x82864\n write 0x3ef2e 0xf9c8 0x1bbae\n write 0x67e05 0xcb5a 0x4e8f6\n mapread 0x57781 0x85b6 0x7495f\n copy_range 0x5d3d 0x10329 0x54fac 0x7495f\n write 0x64710 0x1c2b 0x7495f\n mapread 0x64000 0x1000 0x7495f\n\non cifs with the default cache option.\n\nIt shows read-gaps on folio 0x64 failing with a short read (ie. it hits\nEOF) if the FMODE_READ check is commented out in netfs_perform_write():\n\n if (//(file-\u003ef_mode \u0026 FMODE_READ) ||\n netfs_is_cache_enabled(ctx)) {\n\nand no fscache. This was initially found with the generic/522 xfstest.",
"id": "GHSA-hrh3-6x34-5fxf",
"modified": "2026-07-19T18:31:54Z",
"published": "2026-07-19T18:31:53Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64159"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4543a4d737944134a1394afe797622546fbcc98a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5cd5207de519ef0c085f4f559adf5eefcb4c5202"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.