CVE-2022-49295: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: nbd: call genl_unregister_family() first in nbd_cleanup() Otherwise there may be race between module removal and the handling of netlink command, which can lead to the oops as shown below: BUG: kernel NULL pointer dereference, address: 0000000000000098 Oops: 0002 [#1] SMP PTI CPU: 1 PID: 31299 Comm: nbd-client Tainted: G E 5.14.0-rc4 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:down_write+0x1a/0x50 Call Trace: start_creating+0x89/0x130 debugfs_create_dir+0x1b/0x130 nbd_start_device+0x13d/0x390 [nbd] nbd_genl_connect+0x42f/0x748 [nbd] genl_family_rcv_msg_doit.isra.0+0xec/0x150 genl_rcv_msg+0xe5/0x1e0 netlink_rcv_skb+0x55/0x100 genl_rcv+0x29/0x40 netlink_unicast+0x1a8/0x250 netlink_sendmsg+0x21b/0x430 ____sys_sendmsg+0x2a4/0x2d0 ___sys_sendmsg+0x81/0xc0 __sys_sendmsg+0x62/0xb0 __x64_sys_sendmsg+0x1f/0x30 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae Modules linked in: nbd(E-)

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CVSS v3.1 Score

4.7

MEDIUM

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	< 4.14.283
linux	linux_kernel	4.15 — 4.19.247
linux	linux_kernel	4.20 — 5.4.198
linux	linux_kernel	5.5 — 5.10.122
linux	linux_kernel	5.11 — 5.15.47
linux	linux_kernel	5.16 — 5.17.15
linux	linux_kernel	5.18 — 5.18.4

References

Advisories & Patches

https://git.kernel.org/stable/c/013a79f1b5c89290e2e97f1ebf14b14e0cf5fe5c https://git.kernel.org/stable/c/06c4da89c24e7023ea448cadf8e9daf06a0aae6e https://git.kernel.org/stable/c/1be608e1ee1f222464b2856bda9b85ab5184a33e https://git.kernel.org/stable/c/3d5da1ffba3388c2ae2e6c598855a4d887d3bf79 https://git.kernel.org/stable/c/6f505bbb8063fd3a238a4239d2d8c165e5279f6f https://git.kernel.org/stable/c/8a1435c862ea09b06be7acda325128dc08458e25 https://git.kernel.org/stable/c/c0868f6e728c3c28bef0e8bee89d2daf86a8bbca https://git.kernel.org/stable/c/cbeafa7a79d08ecdb55f8f1d41a11323d0f709db

Frequently Asked Questions

What is CVE-2022-49295? +

In the Linux kernel, the following vulnerability has been resolved: nbd: call genl_unregister_family() first in nbd_cleanup() Otherwise there may be race between module removal and the handling of netlink command, which can lead to the oops as shown below: BUG: kernel NULL pointer dereference, address: 0000000000000098 Oops: 0002 [#1] SMP PTI CPU: 1 PID: 31299 Comm: nbd-client Tainted: G E 5.14.0-rc4 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:down_write+0x1a/0x50 Call Trace: start_creating+0x89/0x130 debugfs_create_dir+0x1b/0x130 nbd_start_device+0x13d/0x390 [nbd] nbd_genl_connect+0x42f/0x748 [nbd] genl_family_rcv_msg_doit.isra.0+0xec/0x150 genl_rcv_msg+0xe5/0x1e0 netlink_rcv_skb+0x55/0x100 genl_rcv+0x29/0x40 netlink_unicast+0x1a8/0x250 netlink_sendmsg+0x21b/0x430 ____sys_sendmsg+0x2a4/0x2d0 ___sys_sendmsg+0x81/0xc0 __sys_sendmsg+0x62/0xb0 __x64_sys_sendmsg+0x1f/0x30 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae Modules linked in: nbd(E-) It has a CVSS v3.1 base score of 4.7 (MEDIUM).

How severe is CVE-2022-49295? +

CVE-2022-49295 has a CVSS v3.1 score of 4.7 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2022-49295? +

CVE-2022-49295 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2022-49295? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2022-49295