CVE-2024-38587 is a medium severity vulnerability identified in the Linux kernel's speakup component, which is a screen reader subsystem designed to assist visually impaired users by providing speech output. The vulnerability arises from a programming error involving the misuse of sizeof() instead of ARRAY_SIZE() when handling a buffer pointer "buf" that is an array of 16-bit unsigned integers (u16). Specifically, the code uses sizeof(buf) to determine the buffer size, which returns 512 bytes, whereas the correct approach is to use ARRAY_SIZE(buf), which returns 256 elements. This discrepancy can lead to out-of-bounds access beyond the intended buffer size. Although the vulnerability does not impact confidentiality or integrity directly, it can affect availability by causing potential memory corruption or crashes within the speakup module. The CVSS 3.1 base score is 5.3, reflecting a network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no impact on confidentiality or integrity (C:N/I:N), but some impact on availability (A:L). There are no known exploits in the wild at the time of publication, and the issue has been resolved in recent Linux kernel versions. The vulnerability affects multiple Linux kernel commits identified by their hashes, indicating it is present in several recent kernel builds prior to the patch. The root cause is a classic off-by-one or buffer boundary error, which can be exploited remotely without authentication or user interaction, but the impact is limited to denial of service or instability rather than privilege escalation or data leakage.

For European organizations, the primary impact of CVE-2024-38587 lies in potential service disruption or denial of service on Linux systems that utilize the speakup screen reader module. While speakup is a niche component mostly relevant for accessibility, its failure could affect users relying on assistive technologies, potentially violating accessibility compliance requirements under EU regulations such as the European Accessibility Act. Additionally, if the vulnerability triggers kernel crashes or instability, it could impact critical Linux-based infrastructure, servers, or embedded devices, leading to downtime or degraded service availability. However, since the vulnerability does not allow privilege escalation or data compromise, the risk to sensitive information or system integrity is minimal. Organizations with Linux deployments in sectors such as healthcare, public services, or government—where accessibility and uptime are critical—should prioritize patching. The lack of known exploits reduces immediate risk, but proactive mitigation is advised to maintain compliance and operational stability.

1. Apply the official Linux kernel patches that fix the sizeof() vs ARRAY_SIZE() misuse in the speakup module as soon as they become available in your distribution's kernel updates. 2. For organizations compiling custom kernels, ensure the kernel source is updated to include the fix before deployment. 3. Disable the speakup module if it is not required in your environment to eliminate exposure. 4. Implement kernel crash monitoring and alerting to detect any instability potentially related to this vulnerability. 5. Conduct accessibility impact assessments to ensure that disabling or patching speakup does not adversely affect users relying on assistive technologies. 6. Maintain up-to-date inventory of Linux kernel versions in use across your infrastructure to identify vulnerable systems quickly. 7. Engage with Linux distribution vendors for timely security advisories and patches related to this CVE. 8. Test patches in staging environments to verify stability before production rollout, especially in mission-critical systems.