CVE-2023-54203

Critical

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix slab-out-of-bounds in init_smb2_rsp_hdr When smb1 mount fails, KASAN detect slab-out-of-bounds in init_smb2_rsp_hdr like the following one. For smb1 negotiate(56bytes) , init_smb2_rsp_hdr() for smb2 is called. The issue occurs while handling smb1 negotiate as smb2 server operations. Add smb server operations for smb1 (get_cmd_val, init_rsp_hdr, allocate_rsp_buf, check_user_session) to handle smb1 negotiate so that smb2 server operation does not handle it. [ 411.400423] CIFS: VFS: Use of the less secure dialect vers=1.0 is not recommended unless required for access to very old servers [ 411.400452] CIFS: Attempting to mount \\192.168.45.139\homes [ 411.479312] ksmbd: init_smb2_rsp_hdr : 492 [ 411.479323] ================================================================== [ 411.479327] BUG: KASAN: slab-out-of-bounds in init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd] [ 411.479369] Read of size 16 at addr ffff888488ed0734 by task kworker/14:1/199 [ 411.479379] CPU: 14 PID: 199 Comm: kworker/14:1 Tainted: G OE 6.1.21 #3 [ 411.479386] Hardware name: ASUSTeK COMPUTER INC. Z10PA-D8 Series/Z10PA-D8 Series, BIOS 3801 08/23/2019 [ 411.479390] Workqueue: ksmbd-io handle_ksmbd_work [ksmbd] [ 411.479425] Call Trace: [ 411.479428] <TASK> [ 411.479432] dump_stack_lvl+0x49/0x63 [ 411.479444] print_report+0x171/0x4a8 [ 411.479452] ? kasan_complete_mode_report_info+0x3c/0x200 [ 411.479463] ? init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd] [ 411.479497] kasan_report+0xb4/0x130 [ 411.479503] ? init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd] [ 411.479537] kasan_check_range+0x149/0x1e0 [ 411.479543] memcpy+0x24/0x70 [ 411.479550] init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd] [ 411.479585] handle_ksmbd_work+0x109/0x760 [ksmbd] [ 411.479616] ? _raw_spin_unlock_irqrestore+0x50/0x50 [ 411.479624] ? smb3_encrypt_resp+0x340/0x340 [ksmbd] [ 411.479656] process_one_work+0x49c/0x790 [ 411.479667] worker_thread+0x2b1/0x6e0 [ 411.479674] ? process_one_work+0x790/0x790 [ 411.479680] kthread+0x177/0x1b0 [ 411.479686] ? kthread_complete_and_exit+0x30/0x30 [ 411.479692] ret_from_fork+0x22/0x30 [ 411.479702] </TASK>

Package Linux Kernel
Published 2025-12-30
Last modified 2026-08-04
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

9.1

out of 10
Critical
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Affected versions

Linux kernel versions 5.15.105, 6.1.22, 6.2.9 and later are affected. Fixed in 5.15.145, 6.1.24, 6.2.11 and their respective stable series.

Affected from
≥ 5.15.105 ≥ 6.1.22 ≥ 6.2.9
Fixed in
✓ 5.15.145 5.15.x ✓ 6.1.24 6.1.x ✓ 6.2.11 6.2.x

Frequently asked questions

  • What is CVE-2023-54203?

    CVE-2023-54203 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.1 out of 10 . It affects Linux kernel versions from 5.15.105 onward and has been patched in 5.15.145, 6.1.24 and 6.2.11. CVE-2023-54203 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2023-54203?

    CVE-2023-54203 has a CVSS score of 9.1 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H .

  • Is there a patch available for CVE-2023-54203?

    Yes. CVE-2023-54203 has been patched. Fixed versions include 5.15.145, 6.1.24 and 6.2.11. If you are running Linux kernel 5.15.105 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2023-54203 actively exploited?

    No. CVE-2023-54203 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.