CyberSecBulletin
CVE-2026-43055NVD status: Modified

Linux: Use of Uninitialized Variable

Published Updated By the CyberSecBulletin desk

CVE-2026-43055 is a high-severity use of uninitialized variable vulnerability in Linux, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions ce54802fe6bb78eb0feffc66fed6a45d41ffc3ab, 4eaff1728d0e69b95933412241bbccf4f797dba8, 01f784fc9d0ab2a6dac45ee443620e517cb2a19b as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.36% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to ce54802fe6bb78eb0feffc66fed6a45d41ffc3ab or 4eaff1728d0e69b95933412241bbccf4f797dba8 or 01f784fc9d0ab2a6dac45ee443620e517cb2a19b, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.18.22 or 6.19.12, whichever matches your release line, or a later version.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux732f25a2895a8c1c54fb56544f0b1e23770ef4d7 up to, but not including, ce54802fe6bb78eb0feffc66fed6a45d41ffc3ab; 732f25a2895a8c1c54fb56544f0b1e23770ef4d7 up to, but not including, 4eaff1728d0e69b95933412241bbccf4f797dba8; 732f25a2895a8c1c54fb56544f0b1e23770ef4d7 up to, but not including, 01f784fc9d0ab2a6dac45ee443620e517cb2a19b; 6.16ce54802fe6bb78eb0feffc66fed6a45d41ffc3ab, 4eaff1728d0e69b95933412241bbccf4f797dba8, 01f784fc9d0ab2a6dac45ee443620e517cb2a19b
LinuxLinux Kernel6.16 up to, but not including, 6.18.22; 6.19 up to, but not including, 6.19.12; 7.06.18.22, 6.19.12

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA.

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use of Uninitialized Variable

The code uses a variable that has not been initialized, leading to unpredictable or unintended results.

How developers prevent this class of flaw

  • Ensure that critical variables are initialized before first use.
  • Most compilers will complain about the use of uninitialized variables if warnings are turned on.
  • When using a language that does not require explicit declaration of variables, run or compile the software in a mode that reports undeclared or unknown variables. This may indicate the presence of a typographic error in the variable's name.

More Use of Uninitialized Variable vulnerabilities (CWE-457)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use of Uninitialized Variable vulnerabilities

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