btrfs: reserve enough transaction items for qgroup ioctls
In the Linux kernel, the following vulnerability has been resolved: btrfs: reserve enough transaction items for qgroup ioctls Currently our qgroup ioctls don't reserve any space, they just do a transaction join, which does not reserve any space, neither for the quota tree updates nor for the delayed refs generated when updating the quota tree. The quota root uses the global block reserve, which is fine most of the time since we don't expect a lot of updates to the quota root, or to be too close to -ENOSPC such that other critical metadata updates need to resort to the global reserve. However this is not optimal, as not reserving proper space may result in a transaction abort due to not reserving space for delayed refs and then abusing the use of the global block reserve. For example, the following reproducer (which is unlikely to model any real world use case, but just to illustrate the problem), triggers such a transaction abort due to -ENOSPC when running delayed refs: $ cat test.sh #!/bin/bash DEV=/dev/nullb0 MNT=/mnt/nullb0 umount $DEV &> /dev/null # Limit device to 1G so that it's much faster to reproduce the issue. mkfs.btrfs -f -b 1G $DEV mount -o commit=600 $DEV $MNT fallocate -l 800M $MNT/filler btrfs quota enable $MNT for ((i = 1; i <= 400000; i++)); do btrfs qgroup create 1/$i $MNT done umount $MNT When running this, we can see in dmesg/syslog that a transaction abort happened: [436.490] BTRFS error (device nullb0): failed to run delayed ref for logical 30408704 nu
CVE-2026-43338
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-2026-43338
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": "5d13a37bd5327220e13329943d1228acfbe5934a",
"lessThan": "320942ce316a17b104b5814db55e42a42c2442cf",
"versionType": "git"
},
{
"status": "affected",
"version": "5d13a37bd5327220e13329943d1228acfbe5934a",
"lessThan": "bb6eb33c908edbbb4d92abdc0c6c87f21b4952e8",
"versionType": "git"
},
{
"status": "affected",
"version": "5d13a37bd5327220e13329943d1228acfbe5934a",
"lessThan": "cf930a651eef6f8d915bf0ccd60c2045974f870c",
"versionType": "git"
},
{
"status": "affected",
"version": "5d13a37bd5327220e13329943d1228acfbe5934a",
"lessThan": "386f5e16a383101a68e195c806b4eedb233cd1d3",
"versionType": "git"
},
{
"status": "affected",
"version": "5d13a37bd5327220e13329943d1228acfbe5934a",
"lessThan": "f9a4e3015db1aeafbef407650eb8555445ca943e",
"versionType": "git"
}
],
"programFiles": [
"fs/btrfs/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": "3.6"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.6",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.81",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.22",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.12",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/btrfs/ioctl.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-43338
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #46292 · Revision 1
- Added to Heist Feed
- Publisher date