CVE-2024-39277 is a high-severity vulnerability in the Linux kernel related to the dma-mapping benchmark code, specifically in handling NUMA (Non-Uniform Memory Access) node identifiers. The vulnerability arises from improper handling of the special NUMA_NO_NODE value (-1) within the function cpumask_of_node(), which is called inside do_map_benchmark(). This leads to an out-of-bounds array access, as cpumask_of_node() attempts to index an array with -1, resulting in undefined behavior and triggering an Undefined Behavior Sanitizer (UBSAN) report for array-index-out-of-bounds. The root cause is that while the node ID is checked in map_benchmark_ioctl(), the NUMA_NO_NODE case is not properly handled later in the code path. This flaw is classified as CWE-125 (Out-of-bounds Read). The vulnerability affects Linux kernel versions around 6.9.0-rc6 and potentially other versions using the affected code. Exploitation requires local privileges with low privileges (PR:L) and no user interaction (UI:N), but the attack vector is local (AV:L), meaning an attacker must have some level of access to the system. The impact is severe, with confidentiality, integrity, and availability all rated high (C:H/I:H/A:H), indicating that exploitation could lead to full system compromise, including privilege escalation or denial of service. The vulnerability was discovered and reported by the Linux Verification Center (linuxtesting.org) and has been publicly disclosed with a CVSS v3.1 score of 7.8. There are no known exploits in the wild at the time of publication, and no patch links were provided in the source information, suggesting that mitigation may require kernel updates once available or manual code fixes. The vulnerability specifically affects kernel code related to DMA mapping benchmarks and NUMA node handling, which are critical for performance and resource management in multi-processor systems.

For European organizations, this vulnerability poses a significant risk primarily to servers and systems running affected Linux kernel versions, especially those deployed in data centers, cloud infrastructures, and high-performance computing environments that utilize NUMA architectures. Exploitation could allow a local attacker or malicious insider to escalate privileges, potentially gaining root access, leading to unauthorized data access, system manipulation, or disruption of critical services. Given the high impact on confidentiality, integrity, and availability, this could result in data breaches, service outages, or compromise of sensitive infrastructure. Organizations relying on Linux-based systems for critical operations, including financial institutions, government agencies, and industrial control systems, could face operational disruptions and regulatory compliance issues under GDPR if personal data is exposed. The requirement for local access limits remote exploitation, but insider threats or attackers who gain initial footholds through other vulnerabilities could leverage this flaw to deepen their control. The lack of known exploits currently reduces immediate risk but does not eliminate the threat, especially as proof-of-concept code may emerge following public disclosure.

European organizations should prioritize updating their Linux kernels to versions where this vulnerability is patched once official updates are released by their Linux distribution vendors. Until patches are available, organizations should: 1) Restrict local access to critical Linux systems by enforcing strict access controls and monitoring for unauthorized logins or suspicious activity. 2) Employ kernel hardening techniques such as enabling kernel address space layout randomization (KASLR) and using security modules like SELinux or AppArmor to limit the impact of potential exploits. 3) Disable or restrict access to the dma_map_benchmark ioctl interface if it is not required, reducing the attack surface. 4) Monitor system logs and use security tools to detect unusual kernel behavior or crashes related to UBSAN reports. 5) Conduct thorough audits of user privileges and remove unnecessary local accounts or services that could be leveraged for local exploitation. 6) Prepare incident response plans specifically for Linux kernel compromises, including rapid patch deployment and system recovery procedures. These steps go beyond generic advice by focusing on controlling local access vectors and minimizing exposure of the vulnerable kernel interfaces.