CVE-2023-53572
Description
A use-after-free flaw was found in the Linux kernel's i.MX system control unit clock driver in the error cleanup path. A local user can trigger this issue during clock initialization failure scenarios on i.MX hardware with System Control Unit firmware, where the cleanup loop incorrectly uses a standard list iterator instead of the safe variant while freeing clock structures. This causes the kernel to dereference freed memory when traversing to the next list element, resulting in memory corruption that can lead to a crash or denial of service.
Statement
The bug appears in the cleanup path that executes when SCU clock registration fails. The code walks a linked list of clock structures, freeing each one, but uses list_for_each_entry() instead of list_for_each_entry_safe(). Since the macro dereferences the current entry to find the next pointer, freeing the entry first creates a use-after-free when the loop tries to advance. Exploitation requires triggering a clock initialization failure, which typically happens only during early boot on specific i.MX platforms with SCU firmware (like i.MX8QM or i.MX8QXP).
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 | 7.8 | 7 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | High | Low | High |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | High | High |
| Integrity Impact | None | High | 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:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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