btrfs: fix xattr replace when multiple xattrs are packed in the same item
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix xattr replace when multiple xattrs are packed in the same item If we have a btrfs_dir_item item that packs multiple xattrs and then we replace the value of one of them (with the setxattr(2) family of syscalls) with another value of a different size, we end up not having a fully initialized btrfs_dir_item, resulting in a corruption that the tree checker will detect at extent buffer writeback time. This is because in btrfs_setxattr() when we find a btrfs_dir_item with multiple xattrs (due to the crc32c hash of their name being the same) we delete one of the xattr items (btrfs_dir_item) and then insert a new one, but the deletion and insertion results in shifting existing data in the leaf and therefore when the new value of a xattr has a different size, the new btrfs_dir_item is placed in a leaf section that was not initialized and we only copy the value's data and set the value's length in the new btrfs_dir_item, without setting the name, the name's length, the key (which must be all zeroes for xattrs), flags (BTRFS_FT_XATTR) and transaction ID. The following script reproduces the issue: $ cat test.sh #!/bin/bash DEV=/dev/sdi MNT=/mnt/sdi mkfs.btrfs -f $DEV mount $DEV $MNT touch $MNT/testfile # Add two xattrs that, on btrfs, have the same hash (crc32c) for their # name and therefore are packed into the same btrfs_dir_item. setfattr -n user.foobar -v 123 $MNT/testfile setfattr -n user.WvG1c1Td -v qwer
CVE-2026-98959
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-2026-98959
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": [
{
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"version": "5f5bc6b1e2d5a6f827bc860ef2dc5b6f365d1339",
"lessThan": "7a53bb4668b319fc6c8a3ce2c21635125c7d2712",
"versionType": "git"
},
{
"status": "affected",
"version": "5f5bc6b1e2d5a6f827bc860ef2dc5b6f365d1339",
"lessThan": "5877d7138cc4359d26fd7b010eedfd1b3162348f",
"versionType": "git"
},
{
"status": "affected",
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"lessThan": "a97114b9b00ed3d05156f3b2ddbf797296260389",
"versionType": "git"
},
{
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"lessThan": "c1803697a60f22743aa28ad522f805e92d45e3f0",
"versionType": "git"
},
{
"status": "affected",
"version": "5f5bc6b1e2d5a6f827bc860ef2dc5b6f365d1339",
"lessThan": "858bee1c77857aabcc2327cd32dd8266332de332",
"versionType": "git"
},
{
"status": "affected",
"version": "43f2e3615d181a7028ab797114c5960977669b2a",
"versionType": "git"
},
{
"status": "affected",
"version": "a873146ce4fb025c0b5c1322af5a6bad042f5363",
"versionType": "git"
},
{
"status": "affected",
"version": "02590fd855d1690568b2fa439c942e933221b57a",
"versionType": "git"
},
{
"status": "affected",
"version": "55e97f654cbbbef70f9714f0e113604dd931e360",
"versionType": "git"
},
{
"status": "affected",
"version": "3.10.83",
"lessThan": "3.11",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.12.45",
"lessThan": "3.13",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.14.47",
"lessThan": "3.15",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.18.19",
"lessThan": "3.19",
"versionType": "semver"
}
],
"programFiles": [
"fs/btrfs/xattr.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.19"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.19",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.113",
"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/btrfs/xattr.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98959
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #55712 · Revision 1
- Added to Heist Feed
- Publisher date