ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT
In the Linux kernel, the following vulnerability has been resolved: ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT Reject the EXT4_IOC_MOVE_EXT ioctl early if the donor file does not belong to the same superblock as the original file. Currently, this validation is performed inside ext4_move_extents() by mext_check_validity(), but only after lock_two_nondirectories() has already acquired the inode locks. When the donor fd refers to a file on a different filesystem (e.g., overlayfs), this late validation creates a circular lock dependency: CPU0 (overlayfs write) CPU1 (ext4 ioctl) ---- ---- inode_lock(ovl_inode) mnt_want_write_file(filp) sb_start_write(ext4_sb) [sb_writers] backing_file_write_iter() vfs_iter_write(real_file) file_start_write(real_file) sb_start_write(ext4_sb) [blocked by freeze] lock_two_nondirectories() inode_lock(ovl_inode) [blocked] With a concurrent freeze operation holding sb_writers write side, this forms a deadlock cycle: CPU0 waits for freeze to complete, freeze waits for CPU1's sb_writers reader to exit, CPU1 waits for CPU0's inode lock. Since EXT4_IOC_MOVE_EXT exchanges physical extents between two files, it fundamentally requires both files to reside on the same ext4 filesystem. Moving the superblock check before any lock acquisition is both semantically correct and eliminates the circular dependency by ensuring that cross-filesystem donor fds are rejected before sb_writers or inode locks are taken.
CVE-2026-74307
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-2026-74307
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": "fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a",
"lessThan": "663f184b51492093d408e518efc95ee13b5b4440",
"versionType": "git"
},
{
"status": "affected",
"version": "fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a",
"lessThan": "74796e886ca39fcb0d3fd36ea6a39c62784ab6fb",
"versionType": "git"
},
{
"status": "affected",
"version": "fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a",
"lessThan": "29e07ec352f0ad06c833a18bf47d82c81f55544f",
"versionType": "git"
},
{
"status": "affected",
"version": "fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a",
"lessThan": "fb52013cad9e9b7d3a6a14ea1bcd841e41da7c6c",
"versionType": "git"
},
{
"status": "affected",
"version": "fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a",
"lessThan": "c143957520c6c9b5cd72e0de8b52b814f0c576fe",
"versionType": "git"
}
],
"programFiles": [
"fs/ext4/ioctl.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.18"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.18",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.57",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/ext4/ioctl.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-74307
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #46542 · Revision 1
- Added to Heist Feed
- Publisher date