CVE-2022-50262 in Linux
Summary
by MITRE • 09/15/2025
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: Validate BOOT record_size
When the NTFS BOOT record_size field < 0, it represents a shift value. However, there is no sanity check on the shift result and the sbi->record_bits calculation through blksize_bits() assumes the size always > 256, which could lead to NPD while mounting a malformed NTFS image.
[ 318.675159] BUG: kernel NULL pointer dereference, address: 0000000000000158
[ 318.675682] #PF: supervisor read access in kernel mode
[ 318.675869] #PF: error_code(0x0000) - not-present page
[ 318.676246] PGD 0 P4D 0
[ 318.676502] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 318.676934] CPU: 0 PID: 259 Comm: mount Not tainted 5.19.0 #5
[ 318.677289] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 318.678136] RIP: 0010:ni_find_attr+0x2d/0x1c0
[ 318.678656] Code: 89 ca 4d 89 c7 41 56 41 55 41 54 41 89 cc 55 48 89 fd 53 48 89 d3 48 83 ec 20 65 48 8b 04 25 28 00 00 00 48 89 44 24 180
[ 318.679848] RSP: 0018:ffffa6c8c0297bd8 EFLAGS: 00000246
[ 318.680104] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000080
[ 318.680790] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 318.681679] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[ 318.682577] R10: 0000000000000000 R11: 0000000000000005 R12: 0000000000000080
[ 318.683015] R13: ffff8d5582e68400 R14: 0000000000000100 R15: 0000000000000000
[ 318.683618] FS: 00007fd9e1c81e40(0000) GS:ffff8d55fdc00000(0000) knlGS:0000000000000000
[ 318.684280] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 318.684651] CR2: 0000000000000158 CR3: 0000000002e1a000 CR4: 00000000000006f0
[ 318.685623] Call Trace:
[ 318.686607] <TASK>
[ 318.686872] ? ntfs_alloc_inode+0x1a/0x60
[ 318.687235] attr_load_runs_vcn+0x2b/0xa0
[ 318.687468] mi_read+0xbb/0x250
[ 318.687576] ntfs_iget5+0x114/0xd90
[ 318.687750] ntfs_fill_super+0x588/0x11b0
[ 318.687953] ? put_ntfs+0x130/0x130
[ 318.688065] ? snprintf+0x49/0x70
[ 318.688164] ? put_ntfs+0x130/0x130
[ 318.688256] get_tree_bdev+0x16a/0x260
[ 318.688407] vfs_get_tree+0x20/0xb0
[ 318.688519] path_mount+0x2dc/0x9b0
[ 318.688877] do_mount+0x74/0x90
[ 318.689142] __x64_sys_mount+0x89/0xd0
[ 318.689636] do_syscall_64+0x3b/0x90
[ 318.689998] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 318.690318] RIP: 0033:0x7fd9e133c48a
[ 318.690687] 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
[ 318.691357] RSP: 002b:00007ffd374406c8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
[ 318.691632] RAX: ffffffffffffffda RBX: 0000564d0b051080 RCX: 00007fd9e133c48a
[ 318.691920] RDX: 0000564d0b051280 RSI: 0000564d0b051300 RDI: 0000564d0b0596a0
[ 318.692123] RBP: 0000000000000000 R08: 0000564d0b0512a0 R09: 0000000000000020
[ 318.692349] R10: 00000000c0ed0000 R11: 0000000000000202 R12: 0000564d0b0596a0
[ 318.692673] R13: 0000564d0b051280 R14: 0000000000000000 R15: 00000000ffffffff
[ 318.693007] </TASK>
[ 318.693271] Modules linked in:
[ 318.693614] CR2: 0000000000000158
[ 318.694446] ---[ end trace 0000000000000000 ]---
[ 318.694779] RIP: 0010:ni_find_attr+0x2d/0x1c0
[ 318.694952] Code: 89 ca 4d 89 c7 41 56 41 55 41 54 41 89 cc 55 48 89 fd 53 48 89 d3 48 83 ec 20 65 48 8b 04 25 28 00 00 00 48 89 44 24 180
[ 318.696042] RSP: 0018:ffffa6c8c0297bd8 EFLAGS: 00000246
[ 318.696531] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000080
[ 318.698114] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 318.699286] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[ 318.699795] R10: 0000000000000000 R11: 0000000000000005 R12: 0000000000000080
[ 318.700236] R13: ffff8d5582e68400 R14: 0000000000000100 R15: 0000000000000000
[ 318.700973] FS: 00007fd9e1c81e40(0000) GS:ffff8d55fdc00000(0000) knlGS:0000000000000000
[
---truncated---
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Analysis
by VulDB Data Team • 01/10/2026
The vulnerability CVE-2022-50262 affects the Linux kernel's NTFS file system implementation, specifically within the ntfs3 driver. This flaw arises from inadequate validation of the BOOT record_size field in NTFS file system structures, creating a potential for kernel NULL pointer dereference during mount operations. The vulnerability stems from a lack of sanity checks when processing negative values in the record_size field, which are intended to represent shift values. When such malformed values are encountered, the calculation of sbi->record_bits through blksize_bits() function fails to account for the possibility of sizes less than 256, leading to invalid memory access patterns.
The technical implementation of this vulnerability involves the ntfs3 file system driver attempting to process a malformed NTFS image where the boot record contains a negative record_size value. According to the kernel crash dump, the issue manifests as a NULL pointer dereference at address 0x0000000000000158 during the ni_find_attr function execution. The call trace shows the error propagating through ntfs_fill_super, which is responsible for initializing the superblock during mount operations, ultimately failing in the attr_load_runs_vcn and mi_read functions that handle attribute loading and metadata reading. The kernel's handling of the record_bits calculation through blksize_bits() assumes all sizes are greater than 256, but negative values representing shift operations can result in calculations that produce invalid bit positions, causing memory corruption.
This vulnerability presents a significant operational impact as it can lead to kernel panic and system crashes when attempting to mount maliciously crafted NTFS images. The condition is particularly concerning because it can be triggered through normal file system mount operations without requiring elevated privileges, making it exploitable in various scenarios including removable media insertion or automated mount processes. The kernel's response to this condition is a hard crash with a NULL pointer dereference, which constitutes a denial of service condition that can affect system availability and potentially provide an attacker with information about kernel memory layout. The vulnerability is classified under CWE-476 as NULL pointer dereference, which represents a fundamental security flaw that can lead to system instability and potential privilege escalation.
Mitigation strategies for CVE-2022-50262 primarily involve applying the kernel patch that implements proper validation of the BOOT record_size field before performing bit calculations. The fix requires ensuring that negative values are properly handled and that the resulting record_bits calculation accounts for all possible input values, including those that might represent shift operations. System administrators should ensure their Linux systems are updated with the patched kernel version that addresses this specific validation issue. Additionally, monitoring for unusual mount operations or attempts to access malformed file systems can help detect potential exploitation attempts. The vulnerability also aligns with ATT&CK technique T1499.001 for system network configuration modification and T1059.001 for command and scripting interpreter, as it enables attackers to potentially disrupt system services through mount operations. Organizations should implement regular kernel updates and maintain security monitoring to detect and respond to exploitation attempts targeting this vulnerability.