VulnerabilityPublished 1 May 2026Updated 3 May 2026

CVE-2026-43055: Linux kernel · scsi: target: file: Use kzalloc_flex for aio_cmd

Source GCVE Database

Authoritative record:CVE-2026-43055· High 7.5

Not known to be exploited · CVSS 7.5 High · fixed in ce54802fe6bb78eb0feffc66fed6a45d41ffc3ab : patch Linux kernel soon.

Data as of 27 Oct 2026, 01:03 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in ce54802fe6bb78eb0feffc66fed6a45d41ffc3ab, 4eaff1728d0e69b95933412241bbccf4f797dba8, 01f784fc9d0ab2a6dac45ee443620e517cb2a19b

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 1 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-9xgj-pwp4-prr4

What to do

Upgrade Linux kernel to ce54802fe6bb78eb0feffc66fed6a45d41ffc3ab, 4eaff1728d0e69b95933412241bbccf4f797dba8 or 01f784fc9d0ab2a6dac45ee443620e517cb2a19b.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 732f25a2895a8c1c54fb56544f0b1e23770ef4d7, < ce54802fe6bb78eb0feffc66fed6a45d41ffc3ab	Fixed in ce54802fe6bb78eb0feffc66fed6a45d41ffc3ab
LinuxLinux	Affected ≥ 732f25a2895a8c1c54fb56544f0b1e23770ef4d7, < 4eaff1728d0e69b95933412241bbccf4f797dba8	Fixed in 4eaff1728d0e69b95933412241bbccf4f797dba8
LinuxLinux	Affected ≥ 732f25a2895a8c1c54fb56544f0b1e23770ef4d7, < 01f784fc9d0ab2a6dac45ee443620e517cb2a19b	Fixed in 01f784fc9d0ab2a6dac45ee443620e517cb2a19b
LinuxLinux	Affected =6.16	Fixed in–

AI-suggested

The issue is resolved by applying the fix that uses kzalloc_flex for aio_cmd allocation, which properly initializes the ki_write_stream field to zero. No further mitigation steps are indicated. Patch status is not explicitly confirmed in the provided data; users should consult the official Linux kernel advisories or updates for the fixed version.

Description

CVE-2026-43055 is a high-severity vulnerability in the Linux kernel's SCSI target file subsystem. The issue arises because the aio_cmd->iocb structure is not properly initialized for the ki_write_stream field, which can lead to incorrect write failure status during asynchronous write commands. The flaw is fixed by using kzalloc_flex to allocate aio_cmd, ensuring ki_write_stream is zero-initialized.

Impact

The vulnerability can cause unintended write failures in block device operations, potentially impacting availability. There is no confidentiality or integrity impact reported. The CVSS score of 7.5 reflects a high severity due to the potential denial of service from write failures.

Summary

This vulnerability in the Linux kernel's target_core_file component involves improper initialization of the aio_cmd->iocb's ki_write_stream field. When a write command is executed via fd_execute_rw_aio(), an uninitialized ki_write_stream value may cause the system to incorrectly report a write failure due to the check against max_write_streams. The fix involves allocating aio_cmd with kzalloc_flex, which zeroes the ki_write_stream field, preventing the erroneous failure condition.

CWE-457Use of Uninitialized Variable (opens in a new tab)
Variant weaknessLikelihood of exploit: High
The code uses a variable that has not been initialized, leading to unpredictable or unintended results.
Implementation · Attack Surface Reduction
Ensure that critical variables are initialized before first use.
Build and Compilation · Compilation or Build Hardening
Most compilers will complain about the use of uninitialized variables if warnings are turned on.
Implementation · Operation
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.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Oct 2026, 01:03 UTC

WeaknessesCWE-457

Technical details

References

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