CVE-2023-52646
Description
A flaw was found in the Linux kernel’s Asynchronous I/O (AIO) subsystem. The issue arises due to a NULL pointer dereference (null-deref) when using the mremap() function after a fork operation, specifically on old AIO mappings. The vulnerability occurs because the ioctx_table is set to NULL after the fork, leading to the potential for system crashes when mremap() is called on these outdated mappings. The problem was introduced in Linux kernel version 3.19 and affected various versions up to 6.2, depending on the specific kernel. It was fixed across several versions, including 4.14.306, 4.19.273, 5.4.232, and 6.1.13.
To mitigate this issue, it is recommended to update to the patched kernel versions. The CVSS score for this vulnerability is 5.5, indicating a medium severity, with potential impacts on system availability due to possible crashes triggered by this null pointer dereference.
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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