Vulnerability · Published Dec 30, 2025 · Assigned by Linux

CVE-2023-54203ksmbd: fix slab-out-of-bounds in init_smb2_rsp_hdr

Critical 9.1

In plain English

A critical-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.1Critical
Exploit odds (30 days)0.5%top 53.9% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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, 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>

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Ubuntu:22.04:LTSlinux5.15.0-102.112UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-aws5.15.0-1057.63UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-azure5.15.0-1060.69UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2023-54203
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1060.69.1UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-gcp5.15.0-1055.63UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2023-54203
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-gke5.15.0-1054.59UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1040.46UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2023-54203
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-ibm5.15.0-1050.53UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1052.58UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-kvm5.15.0-1054.59UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-102.112UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2023-54203
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1048.48UBUNTU-CVE-2023-54203
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1025.25UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1012.12UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2023-54203
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2023-54203
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-oracle5.15.0-1055.61UBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-raspi5.15.0-1050.53UBUNTU-CVE-2023-54203
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2023-54203
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2023-54203
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2023-54203
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2023-54203
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1030.34UBUNTU-CVE-2023-54203

Affected products (as reported)

VendorProductVersions
Linux Linux 51a8534c0f35c0401e45f1055f914729cad98bf9 – before 921536046bd165efeb07beef5630aff35cd6a4890b3ec5671ac06829ccebdaeec05acedfec327f42 – before a8334a0c535d0f0b4d64926c8fe0922ed98f7d43cc32cd98a0aee4cc3eb611cbce11795b1aaa738a – before 99a51c673b1d2d0b5a972353401b77612d9cc71339b291b86b5988bf8753c3874d5c773399d09b96 – before dc8289f912387c3bcfbc5d2db29c8947fa207c11
Linux Linux 5.15.105 – before 5.15.1456.1.22 – before 6.1.246.2.9 – before 6.2.11

References