xfs: stop exchanging reflink flags when exchanging mappings
In the Linux kernel, the following vulnerability has been resolved: xfs: stop exchanging reflink flags when exchanging mappings When an exchange covers both files from offset 0 to i_disk_size, xmi_can_exchange_reflink_flags() assumes every mapping moved and hands the reflink flag over to the other file. That assumption is wrong. A file can still own shared blocks past i_disk_size, e.g. after EXCHANGE_RANGE_TO_EOF sets a smaller size without unmapping anything. The flag is cleared anyway, and the next write to such a block happens in place instead of CoW, corrupting the other file that shares it. Commit a23eca88448e ("xfs: fix exchange-range reflink flag clearing issue with INO1_WRITTEN") fixed one instance of this. Rather than add another special case, stop moving the flags. xfs_exchmaps_ensure_reflink() already sets the flag on both inodes before the exchange, so both just keep it. Nothing sets CLEAR_INO{1,2}_REFLINK anymore. Intents logged by older kernels may still carry them; recovery already masks them off, so they stay in the log format mask and are ignored. XFS_IOC_SWAPEXT has the same problem: it moves the reflink flag from one inode to the other along with the extents. Just removing that is not enough here: the exchange path flags both inodes up front in xfs_exchmaps_ensure_reflink(), but swapext has no such step, so the inode receiving the shared extents would be left without the flag. Set it on both inodes instead, and make sure both have a CoW fork, since an inode
CVE-2026-98975
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-98975
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "f0bc4d134b46607967bda1205ce3226a1bd95f42",
"lessThan": "1fa2f3a7ef7ee0f2503a4b0afe24bc8c9d0820be",
"versionType": "git"
},
{
"status": "affected",
"version": "f0bc4d134b46607967bda1205ce3226a1bd95f42",
"lessThan": "7d3b9b2c9dc57f93f36c716ab752548cb4db9900",
"versionType": "git"
},
{
"status": "affected",
"version": "f0bc4d134b46607967bda1205ce3226a1bd95f42",
"lessThan": "4756c94260e69ce42612b8220c3614f02f7a11d5",
"versionType": "git"
},
{
"status": "affected",
"version": "f0bc4d134b46607967bda1205ce3226a1bd95f42",
"lessThan": "d84d6c1a7f1e2de9e601703a326a4c1b7b421943",
"versionType": "git"
}
],
"programFiles": [
"fs/xfs/libxfs/xfs_exchmaps.c",
"fs/xfs/libxfs/xfs_log_format.h",
"fs/xfs/xfs_bmap_util.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.9"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.9",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.114",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.57",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.11",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/xfs/libxfs/xfs_exchmaps.c",
"fs/xfs/libxfs/xfs_log_format.h",
"fs/xfs/xfs_bmap_util.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98975
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #55716 · Revision 1
- Added to Heist Feed
- Publisher date