CVE-2024-49863

MEDIUM EPSS 20.3%
Published Oct 21, 20241y ago · Modified Jun 17, 20262w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Oct 21, 2024 1y ago
Last Modified Jun 17, 2026 2w ago

Description

In the Linux kernel, the following vulnerability has been resolved: vhost/scsi: null-ptr-dereference in vhost_scsi_get_req() Since commit 3f8ca2e115e5 ("vhost/scsi: Extract common handling code from control queue handler") a null pointer dereference bug can be triggered when guest sends an SCSI AN request. In vhost_scsi_ctl_handle_vq(), `vc.target` is assigned with `&v_req.tmf.lun[1]` within a switch-case block and is then passed to vhost_scsi_get_req() which extracts `vc->req` and `tpg`. However, for a `VIRTIO_SCSI_T_AN_*` request, tpg is not required, so `vc.target` is set to NULL in this branch. Later, in vhost_scsi_get_req(), `vc->target` is dereferenced without being checked, leading to a null pointer dereference bug. This bug can be triggered from guest. When this bug occurs, the vhost_worker process is killed while holding `vq->mutex` and the corresponding tpg will remain occupied indefinitely. Below is the KASAN report: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 PID: 840 Comm: poc Not tainted 6.10.0+ #1 Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:vhost_scsi_get_req+0x165/0x3a0 Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 2b 02 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 65 30 4c 89 e2 48 c1 ea 03 <0f> b6 04 02 4c 89 e2 83 e2 07 38 d0 7f 08 84 c0 0f 85 be 01 00 00 RSP: 0018:ffff888017affb50 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffff88801b000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888017affcb8 RBP: ffff888017affb80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffff888017affc88 R14: ffff888017affd1c R15: ffff888017993000 FS: 000055556e076500(0000) GS:ffff88806b100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000200027c0 CR3: 0000000010ed0004 CR4: 0000000000370ef0 Call Trace: <TASK> ? show_regs+0x86/0xa0 ? die_addr+0x4b/0xd0 ? exc_general_protection+0x163/0x260 ? asm_exc_general_protection+0x27/0x30 ? vhost_scsi_get_req+0x165/0x3a0 vhost_scsi_ctl_handle_vq+0x2a4/0xca0 ? __pfx_vhost_scsi_ctl_handle_vq+0x10/0x10 ? __switch_to+0x721/0xeb0 ? __schedule+0xda5/0x5710 ? __kasan_check_write+0x14/0x30 ? _raw_spin_lock+0x82/0xf0 vhost_scsi_ctl_handle_kick+0x52/0x90 vhost_run_work_list+0x134/0x1b0 vhost_task_fn+0x121/0x350 ... </TASK> ---[ end trace 0000000000000000 ]--- Let's add a check in vhost_scsi_get_req. [whitespace fixes]

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
20.3% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-476 NULL Pointer Dereference Memory Safety

Affected Products 8

VendorProductVersionRange
linuxlinux_kernel*≥4.20  –  <5.10.227
linuxlinux_kernel*≥5.11  –  <5.15.168
linuxlinux_kernel*≥5.16  –  <6.1.113
linuxlinux_kernel*≥6.2  –  <6.6.55
linuxlinux_kernel*≥6.7  –  <6.10.14
linuxlinux_kernel*≥6.11  –  <6.11.3
linuxlinux_kernel6.12any
linuxlinux_kernel6.12any

References 9

  • git.kernel.org https://git.kernel.org/stable/c/00fb5b23e1c9cdbe496f5cd6b40367cb895f6c93
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/221af82f606d928ccef19a16d35633c63026f1be
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/25613e6d9841a1f9fb985be90df921fa99f800de
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/46128370a72c431df733af5ebb065c4d48c9ad39
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/61517f33e76d2c5247c1e61e668693afe5b67e6f
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/6592347f06e2b19a624270a85ad4b3ae48c3b241
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/ace9c778a214da9c98d7b69d904d1b0816f4f681
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/00fb5b23e1c9cdbe496f5cd6b40367cb895f6c93
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/221af82f606d928ccef19a16d35633c63026f1be
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/25613e6d9841a1f9fb985be90df921fa99f800de
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/46128370a72c431df733af5ebb065c4d48c9ad39
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/61517f33e76d2c5247c1e61e668693afe5b67e6f
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/6592347f06e2b19a624270a85ad4b3ae48c3b241
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/ace9c778a214da9c98d7b69d904d1b0816f4f681
    Patch