btrfs: skip global block reserve accounting for rescue mounts
In the Linux kernel, the following vulnerability has been resolved: btrfs: skip global block reserve accounting for rescue mounts [BUG] Mounting with rescue=ibadroots after corrupting the block group tree root triggers a NULL pointer dereference: BUG: kernel NULL pointer dereference, address: 0000000000000100 RIP: 0010:btrfs_update_global_block_rsv+0x9d/0x1c0 [btrfs] Call Trace: fill_dummy_bgs+0xd4/0x120 [btrfs] open_ctree+0xc6e/0x1ca0 [btrfs] btrfs_get_tree+0x50d/0xa40 [btrfs] The same crash occurs with a corrupted raid stripe tree root, via btrfs_read_block_groups() instead of fill_dummy_bgs(). [CAUSE] With rescue=ibadroots, btrfs_read_roots() allows the mount to continue when either root cannot be read, leaving the corresponding root pointer NULL while its on-disk feature bit remains set. btrfs_update_global_block_rsv() then dereferences the missing root based on the feature bit alone. [FIX] Rescue mounts are fully read-only and cannot start transactions, so the global reserve is never consumed. Under btrfs_is_full_ro(), mark the reserve as full and return before performing the accounting. And since we need to check if the fs is mount fully RO, export fs_is_full_ro() as btrfs_is_full_ro(), and move it to fs.h. [ Squash the fs_is_full_ro() export commit into this one. ]
CVE-2026-74571
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-2026-74571
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": "8dbfc14fc736eb701089aff09645c3d4ad3decb1",
"lessThan": "ca05d9abde2195cec3d07d0d4d65152d8171078f",
"versionType": "git"
},
{
"status": "affected",
"version": "8dbfc14fc736eb701089aff09645c3d4ad3decb1",
"lessThan": "3a69fae2371a5ee190d4c4bbe5304a753558c1c6",
"versionType": "git"
},
{
"status": "affected",
"version": "8dbfc14fc736eb701089aff09645c3d4ad3decb1",
"lessThan": "969a96479add6bd42d7f7241f99f27b31571a953",
"versionType": "git"
},
{
"status": "affected",
"version": "8dbfc14fc736eb701089aff09645c3d4ad3decb1",
"lessThan": "076349e4c8d11f6b58c4549976a513b2b4dc6df2",
"versionType": "git"
},
{
"status": "affected",
"version": "8dbfc14fc736eb701089aff09645c3d4ad3decb1",
"lessThan": "51a0e8399858621442807a26057bcd1cd3ced046",
"versionType": "git"
},
{
"status": "affected",
"version": "cbec34d3021d47007a0334c634f7053dbaf93d02",
"versionType": "git"
},
{
"status": "affected",
"version": "1e8087589b5cf6fa17adaf57b64cf1656d77dfec",
"versionType": "git"
},
{
"status": "affected",
"version": "6.1.43",
"lessThan": "6.2",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.4.8",
"lessThan": "6.5",
"versionType": "semver"
}
],
"programFiles": [
"fs/btrfs/block-rsv.c",
"fs/btrfs/disk-io.c",
"fs/btrfs/fs.h"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.5"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.5",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"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": "7.1.8",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/btrfs/block-rsv.c",
"fs/btrfs/disk-io.c",
"fs/btrfs/fs.h"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-74571
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #46579 · Revision 1
- Added to Heist Feed
- Publisher date