VDB-266152 · CVE-2021-47504 · GCVE-0-2021-47504

Linux Kernel up to 5.15.7 io_uring io_uring_cancel_generic missing initialization

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4.4	$0-$5k	0.00

Summaryinfo

A vulnerability described as problematic has been identified in Linux Kernel up to 5.15.7. The impacted element is the function io_uring_cancel_generic of the component io_uring. Executing a manipulation can lead to missing initialization. This vulnerability is tracked as CVE-2021-47504. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 5.15.7 and classified as problematic. This vulnerability affects the function io_uring_cancel_generic of the component io_uring. The manipulation with an unknown input leads to a missing initialization vulnerability. The CWE definition for the vulnerability is CWE-456. The product does not initialize critical variables, which causes the execution environment to use unexpected values. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: io_uring: ensure task_work gets run as part of cancelations If we successfully cancel a work item but that work item needs to be processed through task_work, then we can be sleeping uninterruptibly in io_uring_cancel_generic() and never process it. Hence we don't make forward progress and we end up with an uninterruptible sleep warning. While in there, correct a comment that should be IFF, not IIF.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2021-47504 since 05/22/2024. There are known technical details, but no exploit is available.

Upgrading to version 5.15.8 eliminates this vulnerability. Applying the patch 8e12976c0c19/78a780602075 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.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

Operating System

Vendor

Linux

Name

Kernel

Version

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: 4.5
VulDB Meta Temp Score: 4.4

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Missing initialization
CWE: CWE-456 / CWE-453
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

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Kernel 5.15.8
Patch: 8e12976c0c19/78a780602075

Timelineinfo

05/22/2024 🔍
05/24/2024 +2 days 🔍
05/24/2024 +0 days 🔍
09/29/2025 +493 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2021-47504 (🔍)
GCVE (CVE): GCVE-0-2021-47504
GCVE (VulDB): GCVE-100-266152

Entryinfo

Created: 05/24/2024 17:25
Updated: 09/29/2025 19:13
Changes: 05/24/2024 17:25 (57), 09/29/2025 19:13 (13)
Complete: 🔍
Cache ID: 216::103