Description
In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix block_group_tree dirty_list corruption

When the incompat flag EXTENT_TREE_V2 is set, we unconditionally add the
block group tree to the switch_commits list before calling
switch_commit_roots, as we do for the tree root and the chunk root.
However, the block group tree uses normal root dirty tracking and in any
transaction that does an allocation and dirties a block group, the block
group root will already be linked to a list by the dirty_list field and
this use of list_add_tail() is invalid and corrupts the prev/next
members of block_group_root->dirty_list.

This is apparent on a subsequent list_del on the prev if we enable
CONFIG_DEBUG_LIST:

[32.1571] ------------[ cut here ]------------
[32.1572] list_del corruption. next->prev should beffff958890202538, but was ffff9588992bd538. (next=ffff958890201538)
[32.1575] WARNING: lib/list_debug.c:65 at 0x0, CPU#3: sync/607
[32.1583] CPU: 3 UID: 0 PID: 607 Comm: sync Not tainted 6.18.0 #24PREEMPT(none)
[32.1585] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS1.17.0-4.fc41 04/01/2014
[32.1587] RIP: 0010:__list_del_entry_valid_or_report+0x108/0x120
[32.1593] RSP: 0018:ffffaa288287fdd0 EFLAGS: 00010202
[32.1594] RAX: 0000000000000001 RBX: ffff95889326e800 RCX:ffff958890201538
[32.1596] RDX: ffff9588992bd538 RSI: ffff958890202538 RDI:ffffffff82a41e00
[32.1597] RBP: ffff958890202538 R08: ffffffff828fc1e8 R09:00000000ffffefff
[32.1599] R10: ffffffff8288c200 R11: ffffffff828e4200 R12:ffff958890201538
[32.1601] R13: ffff95889326e958 R14: ffff958895c24000 R15:ffff958890202538
[32.1603] FS: 00007f0c28eb5740(0000) GS:ffff958af2bd2000(0000)knlGS:0000000000000000
[32.1605] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[32.1607] CR2: 00007f0c28e8a3cc CR3: 0000000109942005 CR4:0000000000370ef0
[32.1609] Call Trace:
[32.1610] <TASK>
[32.1611] switch_commit_roots+0x82/0x1d0 [btrfs]
[32.1615] btrfs_commit_transaction+0x968/0x1550 [btrfs]
[32.1618] ? btrfs_attach_transaction_barrier+0x23/0x60 [btrfs]
[32.1621] __iterate_supers+0xe8/0x190
[32.1622] ? __pfx_sync_fs_one_sb+0x10/0x10
[32.1623] ksys_sync+0x63/0xb0
[32.1624] __do_sys_sync+0xe/0x20
[32.1625] do_syscall_64+0x73/0x450
[32.1626] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[32.1627] RIP: 0033:0x7f0c28d05d2b
[32.1632] RSP: 002b:00007ffc9d988048 EFLAGS: 00000246 ORIG_RAX:00000000000000a2
[32.1634] RAX: ffffffffffffffda RBX: 00007ffc9d988228 RCX:00007f0c28d05d2b
[32.1636] RDX: 00007f0c28e02301 RSI: 00007ffc9d989b21 RDI:00007f0c28dba90d
[32.1637] RBP: 0000000000000001 R08: 0000000000000001 R09:0000000000000000
[32.1639] R10: 0000000000000000 R11: 0000000000000246 R12:000055b96572cb80
[32.1641] R13: 000055b96572b19f R14: 00007f0c28dfa434 R15:000055b96572b034
[32.1643] </TASK>
[32.1644] irq event stamp: 0
[32.1644] hardirqs last enabled at (0): [<0000000000000000>] 0x0
[32.1646] hardirqs last disabled at (0): [<ffffffff81298817>]copy_process+0xb37/0x2260
[32.1648] softirqs last enabled at (0): [<ffffffff81298817>]copy_process+0xb37/0x2260
[32.1650] softirqs last disabled at (0): [<0000000000000000>] 0x0
[32.1652] ---[ end trace 0000000000000000 ]---

Furthermore, this list corruption eventually (when we happen to add a
new block group) results in getting the switch_commits and
dirty_cowonly_roots lists mixed up and attempting to call update_root
on the tree root which can't be found in the tree root, resulting in a
transaction abort:

[87.8269] BTRFS critical (device nvme1n1): unable to find root key (1 0 0) in tree 1
[87.8272] ------------[ cut here ]------------
[87.8274] BTRFS: Transaction aborted (error -117)
[87.8275] WARNING: fs/btrfs/root-tree.c:153 at 0x0, CPU#4: sync/703
[87.8285] CPU: 4 UID: 0 PID: 703 Comm: sync Not tainted 6.18.0 #25 PREEMPT(none)
[87.8287] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-4.fc41 0
---truncated---
Published: 2026-06-03
Score: 8.4 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The defect originates in the BTRFS implementation of the Linux kernel. When EXTENT_TREE_V2 is enabled the block group tree is added to a switch_commits list by list_add_tail() after it is already linked to a list via its dirty_list field. This misuse breaks the doubly-linked list invariants, corrupting the prev/next pointers. The corruption surfaces during a subsequent list_del and eventually causes a transaction abort when the system tries to update a missing root. The consequences are a crash or data loss in the affected file system, potentially denying service to every user who mounts or accesses the file system.

Affected Systems

All machines running a Linux kernel that includes the BTRFS file system driver with the EXTENT_TREE_V2 incompatibility flag enabled are impacted. This includes recent kernel releases that still expose the bug prior to the fix, as well as older kernels in which the flag may be activated by configuring the file system support. Any distribution using BTRFS under these conditions is therefore vulnerable.

Risk and Exploitability

The CVSS score of 8.4 is assigned. The EPSS score is less than 1%. The vulnerability is not listed in the CISA KEV catalog. The defect requires that the system run a BTRFS volume with EXTENT_TREE_V2 enabled and that a transaction occurs that allocates a block group and dirties the block group. The attack vector is inferred to be local, as it relies on performing file system transactions which typically require root or sufficient permissions, but the impact is severe once triggered. Since no commercial exploit is known, the risk is moderate, yet patching remains recommended to eliminate the crash hazard.

Generated by OpenCVE AI on June 9, 2026 at 23:12 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply any vendor‑supplied kernel update that includes the BTRFS block_group_tree list corruption fix.
  • If an immediate kernel upgrade is not feasible, avoid using the EXTENT_TREE_V2 incompatibility flag when creating or formatting a BTRFS volume; use the default layout or EXTENT_TREE_V1.
  • After updating or reformatting, run btrfs check --repair on affected volumes.

Generated by OpenCVE AI on June 9, 2026 at 23:12 UTC.

Tracking

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Advisories

No advisories yet.

History

Tue, 09 Jun 2026 20:45:00 +0000

Type Values Removed Values Added
Weaknesses NVD-CWE-noinfo

Fri, 05 Jun 2026 06:45:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

 cvssV3_1

{'score': 8.4, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Thu, 04 Jun 2026 02:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-665
CWE-754

Thu, 04 Jun 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-237
References
Metrics threat_severity

None

 cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate

Wed, 03 Jun 2026 19:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-665
CWE-754

Wed, 03 Jun 2026 17:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: btrfs: fix block_group_tree dirty_list corruption When the incompat flag EXTENT_TREE_V2 is set, we unconditionally add the block group tree to the switch_commits list before calling switch_commit_roots, as we do for the tree root and the chunk root. However, the block group tree uses normal root dirty tracking and in any transaction that does an allocation and dirties a block group, the block group root will already be linked to a list by the dirty_list field and this use of list_add_tail() is invalid and corrupts the prev/next members of block_group_root->dirty_list. This is apparent on a subsequent list_del on the prev if we enable CONFIG_DEBUG_LIST: [32.1571] ------------[ cut here ]------------ [32.1572] list_del corruption. next->prev should beffff958890202538, but was ffff9588992bd538. (next=ffff958890201538) [32.1575] WARNING: lib/list_debug.c:65 at 0x0, CPU#3: sync/607 [32.1583] CPU: 3 UID: 0 PID: 607 Comm: sync Not tainted 6.18.0 #24PREEMPT(none) [32.1585] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS1.17.0-4.fc41 04/01/2014 [32.1587] RIP: 0010:__list_del_entry_valid_or_report+0x108/0x120 [32.1593] RSP: 0018:ffffaa288287fdd0 EFLAGS: 00010202 [32.1594] RAX: 0000000000000001 RBX: ffff95889326e800 RCX:ffff958890201538 [32.1596] RDX: ffff9588992bd538 RSI: ffff958890202538 RDI:ffffffff82a41e00 [32.1597] RBP: ffff958890202538 R08: ffffffff828fc1e8 R09:00000000ffffefff [32.1599] R10: ffffffff8288c200 R11: ffffffff828e4200 R12:ffff958890201538 [32.1601] R13: ffff95889326e958 R14: ffff958895c24000 R15:ffff958890202538 [32.1603] FS: 00007f0c28eb5740(0000) GS:ffff958af2bd2000(0000)knlGS:0000000000000000 [32.1605] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [32.1607] CR2: 00007f0c28e8a3cc CR3: 0000000109942005 CR4:0000000000370ef0 [32.1609] Call Trace: [32.1610] <TASK> [32.1611] switch_commit_roots+0x82/0x1d0 [btrfs] [32.1615] btrfs_commit_transaction+0x968/0x1550 [btrfs] [32.1618] ? btrfs_attach_transaction_barrier+0x23/0x60 [btrfs] [32.1621] __iterate_supers+0xe8/0x190 [32.1622] ? __pfx_sync_fs_one_sb+0x10/0x10 [32.1623] ksys_sync+0x63/0xb0 [32.1624] __do_sys_sync+0xe/0x20 [32.1625] do_syscall_64+0x73/0x450 [32.1626] entry_SYSCALL_64_after_hwframe+0x76/0x7e [32.1627] RIP: 0033:0x7f0c28d05d2b [32.1632] RSP: 002b:00007ffc9d988048 EFLAGS: 00000246 ORIG_RAX:00000000000000a2 [32.1634] RAX: ffffffffffffffda RBX: 00007ffc9d988228 RCX:00007f0c28d05d2b [32.1636] RDX: 00007f0c28e02301 RSI: 00007ffc9d989b21 RDI:00007f0c28dba90d [32.1637] RBP: 0000000000000001 R08: 0000000000000001 R09:0000000000000000 [32.1639] R10: 0000000000000000 R11: 0000000000000246 R12:000055b96572cb80 [32.1641] R13: 000055b96572b19f R14: 00007f0c28dfa434 R15:000055b96572b034 [32.1643] </TASK> [32.1644] irq event stamp: 0 [32.1644] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [32.1646] hardirqs last disabled at (0): [<ffffffff81298817>]copy_process+0xb37/0x2260 [32.1648] softirqs last enabled at (0): [<ffffffff81298817>]copy_process+0xb37/0x2260 [32.1650] softirqs last disabled at (0): [<0000000000000000>] 0x0 [32.1652] ---[ end trace 0000000000000000 ]--- Furthermore, this list corruption eventually (when we happen to add a new block group) results in getting the switch_commits and dirty_cowonly_roots lists mixed up and attempting to call update_root on the tree root which can't be found in the tree root, resulting in a transaction abort: [87.8269] BTRFS critical (device nvme1n1): unable to find root key (1 0 0) in tree 1 [87.8272] ------------[ cut here ]------------ [87.8274] BTRFS: Transaction aborted (error -117) [87.8275] WARNING: fs/btrfs/root-tree.c:153 at 0x0, CPU#4: sync/703 [87.8285] CPU: 4 UID: 0 PID: 703 Comm: sync Not tainted 6.18.0 #25 PREEMPT(none) [87.8287] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-4.fc41 0 ---truncated---
Title btrfs: fix block_group_tree dirty_list corruption
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-06-05T06:06:23.688Z

Reserved: 2026-05-13T15:03:33.107Z

Link: CVE-2026-46251

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2026-06-03T18:16:25.603

Modified: 2026-06-09T20:38:23.397

Link: CVE-2026-46251

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-06-03T00:00:00Z

Links: CVE-2026-46251 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-06-09T23:15:16Z

Weaknesses