CVE-2023-54203

EPSS 0.0%
  • Published: 2025-12-30T13:16:08.420

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 \192.168.45.139homes
[ 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]
[ 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]

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How to fix CVE-2023-54203

CVE-2023-54203 is a unknown severity vulnerability affecting the affected product.

Description: 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, […]

Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public

How to Fix:

1 Identify affected systems

- Check if you're running the affected product

2 Immediate actions

- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access

3 Verification

- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)

4 Long-term prevention

- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations

Exploit Difficulty Assessment

HARD
⏱️ Time to Exploit: > 4 hours
🛠️ Skills Required: Advanced security expertise
💰 Public Exploits: Rare or not public

Vulnerability Timeline

Dec 30, 2025
Vulnerability Published

CVE details first published to NVD database

Dec 30, 2025
Imported to Database

Added to this CVE tracking system

Detection Rules & IOCs

No specific detection rules generated for this vulnerability type.

No vendor/product data available.