CVE-2025-37898 addresses a vulnerability in the Linux kernel specifically related to the powerpc64 architecture's ftrace subsystem and module loading process. The issue arises from the function get_stubs_size, which incorrectly assumes that a kernel module must always contain at least one patchable function entry. However, some modules export only data without any code, causing get_stubs_size to return -ENOEXEC. This erroneous return value leads to the section header's size (sh_size) being set to a negative or zero value. During the module loading phase, module_memory_alloc() calls execmem_alloc() with this size after page alignment, resulting in a zero-sized allocation request. The __vmalloc_node_range() function, responsible for allocating virtual memory, rejects zero-sized allocations and returns NULL, causing the module loading to fail. This failure is logged with kernel warnings indicating the absence of __patchable_function_entries and an inability to allocate memory. The fix implemented removes the problematic check entirely, as propagating this error upwards is unhelpful and unnecessary. This correction ensures that modules exporting only data without code can be loaded correctly without triggering allocation failures. The vulnerability does not appear to allow arbitrary code execution or privilege escalation directly but causes denial of service by preventing legitimate module loading on affected systems. No known exploits are reported in the wild, and the issue is specific to the powerpc64 architecture within Linux kernel module loading mechanisms.

For European organizations, the primary impact of CVE-2025-37898 is a potential denial of service condition affecting systems running Linux on powerpc64 architecture. Organizations relying on Linux servers or embedded devices using this architecture may experience failures when loading certain kernel modules, especially those exporting only data. This could disrupt system functionality, delay updates or patches, and complicate maintenance operations. Critical infrastructure or industrial control systems using powerpc64-based Linux devices might face operational interruptions. However, since the vulnerability does not enable code execution or privilege escalation, the risk of direct compromise or data breach is low. The impact is more operational and availability-focused, potentially affecting service continuity and system stability. European entities with specialized hardware or legacy systems using powerpc64 Linux kernels, such as research institutions, telecom providers, or manufacturing sectors, should be particularly attentive. The absence of known exploits reduces immediate threat levels but does not eliminate the need for timely remediation to prevent inadvertent service disruptions.

To mitigate CVE-2025-37898, European organizations should: 1) Apply the official Linux kernel patches that remove the erroneous get_stubs_size check, ensuring compatibility with modules exporting only data. 2) Test kernel updates in controlled environments, particularly on powerpc64 systems, to verify module loading functionality before deployment. 3) Review and audit kernel modules in use to identify those that export data without code, prioritizing their compatibility with patched kernels. 4) Maintain robust system monitoring to detect module loading failures or kernel warnings indicative of this issue. 5) For critical systems, consider fallback mechanisms or redundant architectures to maintain availability during patch rollout. 6) Engage with hardware and software vendors to confirm support and updates for powerpc64 Linux platforms. 7) Document and train system administrators on this specific vulnerability to ensure prompt recognition and response. These targeted steps go beyond generic patching advice by focusing on architecture-specific testing, module auditing, and operational continuity planning.