CVE-2024-43821
Description
A flaw was found in the Linux kernel. A local attacker with elevated privileges could exploit a null pointer dereference vulnerability within the scsi: lpfc component. This occurs when memory allocation fails in the lpfc_xcvr_data_show function, causing a critical pointer to become null. Subsequent operations attempt to use this null pointer, which can lead to a system crash and result in a denial of service.
Mitigation
To mitigate this vulnerability, prevent the `lpfc` kernel module from loading if Fibre Channel storage is not in use. This can be achieved by blacklisting the module.
1. Create `/etc/modprobe.d/blacklist-lpfc.conf` with `blacklist lpfc`.
2. Regenerate the initramfs: `dracut -f -v` (RHEL 7) or `dracut -f --regenerate-all` (RHEL 8/9).
3. Reboot the system.
This action will disable Fibre Channel functionality that relies on the `lpfc` driver.
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 | 4.4 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | High | 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:H/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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