CVE-2025-38542
Description
A flaw was found in the Linux kernel's Appletalk protocol implementation. A local user with low privileges could exploit a device reference count (refcount) leak in the atrtr_create() function. This vulnerability, a type of resource management error, prevents the proper release of device resources. The most important consequence is a Denial of Service (DoS), which could lead to system instability or unresponsiveness.
Mitigation
To mitigate this issue on affected Red Hat Enterprise Linux 6 ELS systems, and as a general hardening measure on other systems where Appletalk is not required, prevent the `appletalk` kernel module from loading. This can be achieved by creating a modprobe configuration file.
Create a file named `/etc/modprobe.d/disable-appletalk.conf` with the following content:
install appletalk /bin/trueAfter creating the file, regenerate the initramfs and reboot the system for the changes to take effect. This may impact functionality if Appletalk services are actively used.
blacklist appletalk
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 | 7.8 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | 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: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
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
An adversary that can cause a resource counter to become inaccurate may be able to create situations where resources are not accounted for and not released, thus causing resources to become scarce for future needs.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An adversary that can cause a resource counter to become inaccurate may be able to force an error that causes the product to crash or exit out of its current operation.
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