CVE-2023-53609
Description
A use-after-free flaw was found in the Linux kernel's SCSI subsystem in the command dispatch error handling. A local user can trigger this issue through specific SCSI device operations that cause dispatch failures, where the code attempts to increment a reference counter on a device structure that may have already been freed after returning from the dispatch function. This results in accessing freed memory, leading to kernel panic or potential memory corruption.
Statement
The vulnerability was introduced by a commit that attempted to fix reference counting by incrementing iorequest_cnt after dispatch. However, the design assumption that cmd->device remains valid after scsi_dispatch_cmd() returns is incorrect—the device structure can be freed during or immediately after dispatch in certain error scenarios. When the code then attempts to access cmd->device->iorequest_cnt, it dereferences freed memory. This race window is narrow and requires specific error conditions during SCSI command dispatch, such as device removal concurrent with I/O operations or certain failure paths in lower-level drivers.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.7 | 5.5 | 7.8 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | High | Low | Low |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | High |
| Integrity Impact | None | None | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/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
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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