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

btrfs: directly free partially initialized fs_info in btrfs_check_leaked_roots()

If fs_info->super_copy or fs_info->super_for_commit allocated failed in
btrfs_get_tree_subvol(), then no need to call btrfs_free_fs_info().
Otherwise btrfs_check_leaked_roots() would access NULL pointer because
fs_info->allocated_roots had not been initialised.

syzkaller reported the following information:
------------[ cut here ]------------
BUG: unable to handle page fault for address: fffffffffffffbb0
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 64c9067 P4D 64c9067 PUD 64cb067 PMD 0
Oops: Oops: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 1402 Comm: syz.1.35 Not tainted 6.15.8 #4 PREEMPT(lazy)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), (...)
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline]
RIP: 0010:refcount_read include/linux/refcount.h:170 [inline]
RIP: 0010:btrfs_check_leaked_roots+0x18f/0x2c0 fs/btrfs/disk-io.c:1230
[...]
Call Trace:
<TASK>
btrfs_free_fs_info+0x310/0x410 fs/btrfs/disk-io.c:1280
btrfs_get_tree_subvol+0x592/0x6b0 fs/btrfs/super.c:2029
btrfs_get_tree+0x63/0x80 fs/btrfs/super.c:2097
vfs_get_tree+0x98/0x320 fs/super.c:1759
do_new_mount+0x357/0x660 fs/namespace.c:3899
path_mount+0x716/0x19c0 fs/namespace.c:4226
do_mount fs/namespace.c:4239 [inline]
__do_sys_mount fs/namespace.c:4450 [inline]
__se_sys_mount fs/namespace.c:4427 [inline]
__x64_sys_mount+0x28c/0x310 fs/namespace.c:4427
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x92/0x180 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f032eaffa8d
[...]

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00017.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

Vendors Products
Linux Subscribe
Linux Kernel Subscribe

No data.

No data.

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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://git.kernel.org/stable/c/0c2b2d4d053e9840e6da6ed581befa20309f281a cve-icon cve-icon
https://git.kernel.org/stable/c/17679ac6df6c4830ba711835aa8cf961be36cfa1 cve-icon cve-icon
https://git.kernel.org/stable/c/b1c2b4e6ffd307720ab6ce42f6749b0c02ba0a73 cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025120401-CVE-2025-40235-4e24@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-40235 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-40235 cve-icon
History

Sat, 06 Dec 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low

Thu, 04 Dec 2025 15:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: btrfs: directly free partially initialized fs_info in btrfs_check_leaked_roots() If fs_info->super_copy or fs_info->super_for_commit allocated failed in btrfs_get_tree_subvol(), then no need to call btrfs_free_fs_info(). Otherwise btrfs_check_leaked_roots() would access NULL pointer because fs_info->allocated_roots had not been initialised. syzkaller reported the following information: ------------[ cut here ]------------ BUG: unable to handle page fault for address: fffffffffffffbb0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 64c9067 P4D 64c9067 PUD 64cb067 PMD 0 Oops: Oops: 0000 [#1] SMP KASAN PTI CPU: 0 UID: 0 PID: 1402 Comm: syz.1.35 Not tainted 6.15.8 #4 PREEMPT(lazy) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), (...) RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline] RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline] RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline] RIP: 0010:refcount_read include/linux/refcount.h:170 [inline] RIP: 0010:btrfs_check_leaked_roots+0x18f/0x2c0 fs/btrfs/disk-io.c:1230 [...] Call Trace: <TASK> btrfs_free_fs_info+0x310/0x410 fs/btrfs/disk-io.c:1280 btrfs_get_tree_subvol+0x592/0x6b0 fs/btrfs/super.c:2029 btrfs_get_tree+0x63/0x80 fs/btrfs/super.c:2097 vfs_get_tree+0x98/0x320 fs/super.c:1759 do_new_mount+0x357/0x660 fs/namespace.c:3899 path_mount+0x716/0x19c0 fs/namespace.c:4226 do_mount fs/namespace.c:4239 [inline] __do_sys_mount fs/namespace.c:4450 [inline] __se_sys_mount fs/namespace.c:4427 [inline] __x64_sys_mount+0x28c/0x310 fs/namespace.c:4427 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x92/0x180 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f032eaffa8d [...]
Title btrfs: directly free partially initialized fs_info in btrfs_check_leaked_roots()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-12-04T15:31:25.785Z

Reserved: 2025-04-16T07:20:57.180Z

Link: CVE-2025-40235

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-12-04T16:16:16.407

Modified: 2025-12-04T17:15:08.283

Link: CVE-2025-40235

cve-icon Redhat

Severity : Low

Publid Date: 2025-12-04T00:00:00Z

Links: CVE-2025-40235 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.