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Linux KernelOperating system · Linux

CVE-2024-40962

MEDIUM · 5.5 CVSS v3.1 Published 2024-07-12
Fix available
A fix is available. Upgrade to 6.6.36 / 6.9.7 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: btrfs: zoned: allocate dummy checksums for zoned NODATASUM writes Shin'ichiro reported that when he's running fstests' test-case btrfs/167 on emulated zoned devices, he's seeing the following NULL pointer dereference in 'btrfs_zone_finish_endio()': Oops: general protection fault, probably for non-canonical address 0xdffffc0000000011: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f] CPU: 4 PID: 2332440 Comm: kworker/u80:15 Tainted: G W 6.10.0-rc2-kts+ #4 Hardware name: Supermicro Super Server/X11SPi-TF, BIOS 3.3 02/21/2020 Workqueue: btrfs-endio-write btrfs_work_helper [btrfs] RIP: 0010:btrfs_zone_finish_endio.part.0+0x34/0x160 [btrfs] RSP: 0018:ffff88867f107a90 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff893e5534 RDX: 0000000000000011 RSI: 0000000000000004 RDI: 0000000000000088 RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed1081696028 R10: ffff88840b4b0143 R11: ffff88834dfff600 R12: ffff88840b4b0000 R13: 0000000000020000 R14: 0000000000000000 R15: ffff888530ad5210 FS: 0000000000000000(0000) GS:ffff888e3f800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f87223fff38 CR3: 00000007a7c6a002 CR4: 00000000007706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> ? __die_body.cold+0x19/0x27 ? die_addr+0x46/0x70 ? exc_general_protection+0x14f/0x250 ? asm_exc_general_protection+0x26/0x30 ? do_raw_read_unlock+0x44/0x70 ? btrfs_zone_finish_endio.part.0+0x34/0x160 [btrfs] btrfs_finish_one_ordered+0x5d9/0x19a0 [btrfs] ? __pfx_lock_release+0x10/0x10 ? do_raw_write_lock+0x90/0x260 ? __pfx_do_raw_write_lock+0x10/0x10 ? __pfx_btrfs_finish_one_ordered+0x10/0x10 [btrfs] ? _raw_write_unlock+0x23/0x40 ? btrfs_finish_ordered_zoned+0x5a9/0x850 [btrfs] ? lock_acquire+0x435/0x500 btrfs_work_helper+0x1b1/0xa70 [btrfs] ? __schedule+0x10a8/0x60b0 ? __pfx___might_resched+0x10/0x10 process_one_work+0x862/0x1410 ? __pfx_lock_acquire+0x10/0x10 ? __pfx_process_one_work+0x10/0x10 ? assign_work+0x16c/0x240 worker_thread+0x5e6/0x1010 ? __pfx_worker_thread+0x10/0x10 kthread+0x2c3/0x3a0 ? trace_irq_enable.constprop.0+0xce/0x110 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x31/0x70 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> Enabling CONFIG_BTRFS_ASSERT revealed the following assertion to trigger: assertion failed: !list_empty(&ordered->list), in fs/btrfs/zoned.c:1815 This indicates, that we're missing the checksums list on the ordered_extent. As btrfs/167 is doing a NOCOW write this is to be expected. Further analysis with drgn confirmed the assumption: >>> inode = prog.crashed_thread().stack_trace()[11]['ordered'].inode >>> btrfs_inode = drgn.container_of(inode, "struct btrfs_inode", \ "vfs_inode") >>> print(btrfs_inode.flags) (u32)1 As zoned emulation mode simulates conventional zones on regular devices, we cannot use zone-append for writing. But we're only attaching dummy checksums if we're doing a zone-append write. So for NOCOW zoned data writes on conventional zones, also attach a dummy checksum.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-476

The code follows a pointer that is null, crashing the process. An attacker who can reliably trigger it turns the crash into a denial of service. The fix is checking for null before use and handling the failure path gracefully.

General guidance for the null pointer dereference class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 6.5, < 6.6.36>= 6.7, < 6.9.7= 6.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.6.36 / 6.9.7 or later
Fixed in 6.6.366.9.7
Vendor patch git.kernel.org →
Recommended fix High confidence

6.6.36+ / 6.9.7+ / 6.10.1+ (Linux kernel stable releases)

  1. Identify the current running kernel version using 'uname -r'
  2. Check if the system is running an affected version: >= 6.5 and < 6.6.36, >= 6.7 and < 6.9.7, or exactly 6.10
  3. If affected, upgrade the Linux kernel to a patched release: 6.6.36 or later in the 6.6.y stable branch, 6.9.7 or later in the 6.9.y stable branch, or 6.10.1 or later in the 6.10.y stable branch
  4. For systems using distribution kernels, check for available updates via the distribution's package manager (e.g., apt update && apt upgrade, yum update, dnf update)
  5. Reboot the system to load the patched kernel
  6. Verify the fix is applied by running 'uname -r' and confirming the version is greater than the affected versions listed
Caveat Kernel upgrades may require system reboot and could introduce compatibility issues with third-party kernel modules; ensure backups and test in non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,850. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

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Peer-ranked notes from engineers who’ve handled CVE-2024-40962 in production — separate from our analysis above.

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