CVE-2022-50739 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: Add null pointer check for inode operations
This adds a sanity check for the i_op pointer of the inode which is returned after reading Root directory MFT record. We should check the i_op is valid before trying to create the root dentry, otherwise we may encounter a NPD while mounting a image with a funny Root directory MFT record.
[ 114.484325] BUG: kernel NULL pointer dereference, address: 0000000000000008
[ 114.484811] #PF: supervisor read access in kernel mode
[ 114.485084] #PF: error_code(0x0000) - not-present page
[ 114.485606] PGD 0 P4D 0
[ 114.485975] Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI
[ 114.486570] CPU: 0 PID: 237 Comm: mount Tainted: G B 6.0.0-rc4 #28
[ 114.486977] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 114.488169] RIP: 0010:d_flags_for_inode+0xe0/0x110
[ 114.488816] Code: 24 f7 ff 49 83 3e 00 74 41 41 83 cd 02 66 44 89 6b 02 eb 92 48 8d 7b 20 e8 6d 24 f7 ff 4c 8b 73 20 49 8d 7e 08 e8 60 241
[ 114.490326] RSP: 0018:ffff8880065e7aa8 EFLAGS: 00000296
[ 114.490695] RAX: 0000000000000001 RBX: ffff888008ccd750 RCX: ffffffff84af2aea
[ 114.490986] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff87abd020
[ 114.491364] RBP: ffff8880065e7ac8 R08: 0000000000000001 R09: fffffbfff0f57a05
[ 114.491675] R10: ffffffff87abd027 R11: fffffbfff0f57a04 R12: 0000000000000000
[ 114.491954] R13: 0000000000000008 R14: 0000000000000000 R15: ffff888008ccd750
[ 114.492397] FS: 00007fdc8a627e40(0000) GS:ffff888058200000(0000) knlGS:0000000000000000
[ 114.492797] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 114.493150] CR2: 0000000000000008 CR3: 00000000013ba000 CR4: 00000000000006f0
[ 114.493671] Call Trace:
[ 114.493890] <TASK>
[ 114.494075] __d_instantiate+0x24/0x1c0
[ 114.494505] d_instantiate.part.0+0x35/0x50
[ 114.494754] d_make_root+0x53/0x80
[ 114.494998] ntfs_fill_super+0x1232/0x1b50
[ 114.495260] ? put_ntfs+0x1d0/0x1d0
[ 114.495499] ? vsprintf+0x20/0x20
[ 114.495723] ? set_blocksize+0x95/0x150
[ 114.495964] get_tree_bdev+0x232/0x370
[ 114.496272] ? put_ntfs+0x1d0/0x1d0
[ 114.496502] ntfs_fs_get_tree+0x15/0x20
[ 114.496859] vfs_get_tree+0x4c/0x130
[ 114.497099] path_mount+0x654/0xfe0
[ 114.497507] ? putname+0x80/0xa0
[ 114.497933] ? finish_automount+0x2e0/0x2e0
[ 114.498362] ? putname+0x80/0xa0
[ 114.498571] ? kmem_cache_free+0x1c4/0x440
[ 114.498819] ? putname+0x80/0xa0
[ 114.499069] do_mount+0xd6/0xf0
[ 114.499343] ? path_mount+0xfe0/0xfe0
[ 114.499683] ? __kasan_check_write+0x14/0x20
[ 114.500133] __x64_sys_mount+0xca/0x110
[ 114.500592] do_syscall_64+0x3b/0x90
[ 114.500930] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 114.501294] RIP: 0033:0x7fdc898e948a
[ 114.501542] Code: 48 8b 0d 11 fa 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 008
[ 114.502716] RSP: 002b:00007ffd793e58f8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
[ 114.503175] RAX: ffffffffffffffda RBX: 0000564b2228f060 RCX: 00007fdc898e948a
[ 114.503588] RDX: 0000564b2228f260 RSI: 0000564b2228f2e0 RDI: 0000564b22297ce0
[ 114.504925] RBP: 0000000000000000 R08: 0000564b2228f280 R09: 0000000000000020
[ 114.505484] R10: 00000000c0ed0000 R11: 0000000000000202 R12: 0000564b22297ce0
[ 114.505823] R13: 0000564b2228f260 R14: 0000000000000000 R15: 00000000ffffffff
[ 114.506562] </TASK>
[ 114.506887] Modules linked in:
[ 114.507648] CR2: 0000000000000008
[ 114.508884] ---[ end trace 0000000000000000 ]---
[ 114.509675] RIP: 0010:d_flags_for_inode+0xe0/0x110
[ 114.510140] Code: 24 f7 ff 49 83 3e 00 74 41 41 83 cd 02 66 44 89 6b 02 eb 92 48 8d 7b 20 e8 6d 24 f7 ff 4c 8b 73 20 49 8d 7e 08 e8 60 241
[ 114.511762] RSP: 0018:ffff8880065e7aa8 EFLAGS: 00000296
[ 114.512401] RAX: 0000000000000001 RBX: ffff888008ccd750 RCX: ffffffff84af2aea
[ 114.51
---truncated---
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Analysis
by VulDB Data Team • 04/21/2026
The vulnerability CVE-2022-50739 resides within the Linux kernel's ntfs3 filesystem driver, specifically addressing a null pointer dereference condition that occurs during the mounting process of NTFS filesystems. This flaw manifests when the kernel attempts to read the Root directory MFT (Master File Table) record and subsequently creates a root dentry without validating the inode operations pointer. The issue stems from an insufficient sanity check for the i_op field of the inode structure, which is critical for proper filesystem operation and can lead to kernel crashes when malformed or corrupted MFT records are encountered.
The technical execution of this vulnerability involves a kernel NULL pointer dereference at address 0x0000000000000008, which occurs during the d_flags_for_inode function call. This represents a classic kernel-level null pointer dereference that violates fundamental memory safety principles and can result in system instability or complete system crashes. The call trace indicates the error originates from ntfs_fill_super function when attempting to instantiate the root dentry, which directly correlates with the ntfs3 filesystem driver's handling of root directory metadata.
From a cybersecurity perspective, this vulnerability represents a potential denial-of-service attack vector that could be exploited by malicious actors to crash systems running Linux kernels with ntfs3 support. The flaw aligns with CWE-476, which specifically addresses null pointer dereference vulnerabilities in software systems. The kernel's failure to validate the inode operations pointer before utilizing it demonstrates a lack of proper input validation and defensive programming practices, which are essential for maintaining system stability and preventing unauthorized system compromise.
The operational impact of this vulnerability extends beyond simple system crashes, as it can affect any system attempting to mount NTFS filesystems, particularly those with corrupted or malformed MFT records. Attackers could potentially craft specially designed filesystem images that trigger this condition, leading to persistent system unavailability. The vulnerability affects systems using the ntfs3 filesystem driver, which is part of the standard Linux kernel distribution and is commonly used for cross-platform compatibility with Windows systems.
Mitigation strategies for CVE-2022-50739 involve applying the kernel patch that introduces the null pointer check for inode operations, which prevents the kernel from attempting to dereference a null pointer during filesystem mounting. System administrators should prioritize updating their kernels to versions containing the fix, as this vulnerability represents a clear security risk that could be exploited to cause system instability. Additionally, monitoring for unusual mounting behaviors or system crashes related to NTFS filesystems can help detect potential exploitation attempts. The fix itself follows established security practices by implementing proper input validation and defensive programming techniques that prevent null pointer dereference conditions in kernel space operations.