Linux Kernel up to 5.18.3 nbd_alloc_config null pointer dereference

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4.6	$0-$5k	0.00

Summaryinfo

A vulnerability identified as critical has been detected in Linux Kernel up to 5.18.3. Impacted is the function nbd_alloc_config. This manipulation causes null pointer dereference. This vulnerability is handled as CVE-2022-49300. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 5.18.3 and classified as critical. Affected by this vulnerability is the function nbd_alloc_config. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: nbd: fix race between nbd_alloc_config() and module removal When nbd module is being removing, nbd_alloc_config() may be called concurrently by nbd_genl_connect(), although try_module_get() will return false, but nbd_alloc_config() doesn't handle it. The race may lead to the leak of nbd_config and its related resources (e.g, recv_workq) and oops in nbd_read_stat() due to the unload of nbd module as shown below: BUG: kernel NULL pointer dereference, address: 0000000000000040 Oops: 0000 [#1] SMP PTI CPU: 5 PID: 13840 Comm: kworker/u17:33 Not tainted 5.14.0+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Workqueue: knbd16-recv recv_work [nbd] RIP: 0010:nbd_read_stat.cold+0x130/0x1a4 [nbd] Call Trace: recv_work+0x3b/0xb0 [nbd] process_one_work+0x1ed/0x390 worker_thread+0x4a/0x3d0 kthread+0x12a/0x150 ret_from_fork+0x22/0x30 Fixing it by checking the return value of try_module_get() in nbd_alloc_config(). As nbd_alloc_config() may return ERR_PTR(-ENODEV), assign nbd->config only when nbd_alloc_config() succeeds to ensure the value of nbd->config is binary (valid or NULL). Also adding a debug message to check the reference counter of nbd_config during module removal.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2022-49300 since 02/26/2025. The exploitation appears to be difficult. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 225803 (Linux Distros Unpatched Vulnerability : CVE-2022-49300), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.14.283, 4.19.247, 5.4.198, 5.10.122, 5.15.47, 5.17.15 or 5.18.4 eliminates this vulnerability. Applying the patch 165cf2e0019fa6cedc75b456490c41494c34abb4/2573f2375b64280be977431701ed5d33b75b9ad0/8a7da4ced236ce6637fe70f14ca18e718d4bf9e9/122e4adaff2439f1cc18cc7e931980fa7560df5c/71c142f910da44421213ade601bcbd23ceae19fa/2888fa41985f93ed0a6837cfbb06bcbfd7fa2314/d09525720dd5201756f698bee1076de9aefd4602/c55b2b983b0fa012942c3eb16384b2b722caa810 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (225803). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 4.14.282
• 4.19.246
• 5.4.197
• 5.10.121
• 5.15.0
• 5.15.1
• 5.15.2
• 5.15.3
• 5.15.4
• 5.15.5
• 5.15.6
• 5.15.7
• 5.15.8
• 5.15.9
• 5.15.10
• 5.15.11
• 5.15.12
• 5.15.13
• 5.15.14
• 5.15.15
• 5.15.16
• 5.15.17
• 5.15.18
• 5.15.19
• 5.15.20
• 5.15.21
• 5.15.22
• 5.15.23
• 5.15.24
• 5.15.25
• 5.15.26
• 5.15.27
• 5.15.28
• 5.15.29
• 5.15.30
• 5.15.31
• 5.15.32
• 5.15.33
• 5.15.34
• 5.15.35
• 5.15.36
• 5.15.37
• 5.15.38
• 5.15.39
• 5.15.40
• 5.15.41
• 5.15.42
• 5.15.43
• 5.15.44
• 5.15.45
• 5.15.46
• 5.17.0
• 5.17.1
• 5.17.2
• 5.17.3
• 5.17.4
• 5.17.5
• 5.17.6
• 5.17.7
• 5.17.8
• 5.17.9
• 5.17.10
• 5.17.11
• 5.17.12
• 5.17.13
• 5.17.14
• 5.18.0
• 5.18.1
• 5.18.2
• 5.18.3

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.8
VulDB Meta Temp Score: 4.6

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 4.7
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 225803
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2022-49300

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Kernel 4.14.283/4.19.247/5.4.198/5.10.122/5.15.47/5.17.15/5.18.4
Patch: 165cf2e0019fa6cedc75b456490c41494c34abb4/2573f2375b64280be977431701ed5d33b75b9ad0/8a7da4ced236ce6637fe70f14ca18e718d4bf9e9/122e4adaff2439f1cc18cc7e931980fa7560df5c/71c142f910da44421213ade601bcbd23ceae19fa/2888fa41985f93ed0a6837cfbb06bcbfd7fa2314/d09525720dd5201756f698bee1076de9aefd4602/c55b2b983b0fa012942c3eb16384b2b722caa810

Timelineinfo

02/26/2025 🔍
02/26/2025 +0 days 🔍
02/26/2025 +0 days 🔍
04/15/2025 +48 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2022-49300 (🔍)
GCVE (CVE): GCVE-0-2022-49300
GCVE (VulDB): GCVE-100-296851

Entryinfo

Created: 02/26/2025 07:57
Updated: 04/15/2025 10:11
Changes: 02/26/2025 07:57 (58), 03/05/2025 18:14 (2), 04/15/2025 10:11 (10)
Complete: 🔍
Cache ID: 216::103

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