CVE-2026-45857
Description
A flaw was found in the Linux kernel's scsi: csiostor module. This null pointer dereference vulnerability occurs in an error handling path. A local attacker could exploit this to cause a system crash, leading to a Denial of Service (DoS).
Statement
This Moderate-impact null pointer dereference flaw in the Linux kernel's csiostor module could allow a local attacker to trigger a system crash, resulting in a denial of service. The vulnerability specifically affects the error handling path of the csiostor driver, which is primarily used with Chelsio Communications iSCSI adapters.
Mitigation
To prevent exploitation, the `csiostor` kernel module can be blacklisted. Create a file `/etc/modprobe.d/blacklist-csiostor.conf` with the line `blacklist csiostor`. A system reboot is necessary for this change to take effect. This mitigation may affect systems that rely on Chelsio T4/T5/T6 iSCSI/FCoE adapters.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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