Linux Kernel up to 6.18.21/6.19.11 scsi fd_execute_rw_aio ki_write_stream missing initialization

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.18.21/6.19.11 and classified as critical. Impacted is the function fd_execute_rw_aio of the component scsi. Such manipulation of the argument ki_write_stream leads to missing initialization. This vulnerability is listed as CVE-2026-43055. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.21/6.19.11. It has been rated as critical. Affected by this issue is the function fd_execute_rw_aio of the component scsi. The manipulation of the argument ki_write_stream with an unknown input leads to a missing initialization vulnerability. Using CWE to declare the problem leads to CWE-456. The product does not initialize critical variables, which causes the execution environment to use unexpected values. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: scsi: target: file: Use kzalloc_flex for aio_cmd The target_core_file doesn't initialize the aio_cmd->iocb for the ki_write_stream. When a write command fd_execute_rw_aio() is executed, we may get a bogus ki_write_stream value, causing unintended write failure status when checking iocb->ki_write_stream > max_write_streams in the block device. Let's just use kzalloc_flex when allocating the aio_cmd and let ki_write_stream=0 to fix this issue.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-43055 since 05/01/2026. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 05/01/2026).

Upgrading to version 6.18.22 or 6.19.12 eliminates this vulnerability. Applying the patch ce54802fe6bb78eb0feffc66fed6a45d41ffc3ab/4eaff1728d0e69b95933412241bbccf4f797dba8/01f784fc9d0ab2a6dac45ee443620e517cb2a19b 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

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.19.0
• 6.19.1
• 6.19.2
• 6.19.3
• 6.19.4
• 6.19.5
• 6.19.6
• 6.19.7
• 6.19.8
• 6.19.9
• 6.19.10
• 6.19.11

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

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

Discussion