CVE-2025-37850 is a vulnerability identified in the Linux kernel specifically within the PWM (Pulse Width Modulation) driver for MediaTek hardware, located in the function pwm_mediatek_config(). The issue arises due to a divide-by-zero error triggered when the kernel is compiled with the CONFIG_COMPILE_TEST option enabled and the CONFIG_HAVE_CLK option disabled. Under these conditions, the clk_get_rate() function returns zero, leading to a division by zero in the line do_div(resolution, clk_get_rate(pc->clk_pwms[pwm->hwpwm])). This vulnerability is primarily theoretical because the COMPILE_TEST configuration typically overrides dependencies that would select a common clock source, preventing this scenario in most practical builds. However, the flaw was identified and fixed to explicitly check for this error condition, preventing the divide-by-zero. The vulnerability does not appear to have any known exploits in the wild and is related to a compilation-time configuration rather than a runtime flaw affecting typical end-user systems. The fix also addresses a related warning about an unexpected end of section during object tool verification. The affected versions are identified by a specific commit hash, indicating this is a low-level kernel source code issue rather than a widespread binary vulnerability. No CVSS score is assigned, and no known exploits or active attacks have been reported. This vulnerability is primarily of concern to developers and maintainers compiling custom Linux kernels for MediaTek platforms with unusual configuration flags rather than general Linux users or administrators.

For European organizations, the direct impact of CVE-2025-37850 is minimal. The vulnerability is tied to a very specific kernel compile-time configuration that is unlikely to be present in production or standard Linux distributions. Most commercial and enterprise Linux distributions used in Europe do not compile kernels with CONFIG_COMPILE_TEST enabled and CONFIG_HAVE_CLK disabled simultaneously, making exploitation improbable. Furthermore, the vulnerability does not lead to privilege escalation, remote code execution, or data leakage but rather a potential kernel panic or crash if triggered, which could affect system availability during kernel compilation or testing phases. Organizations involved in embedded systems development, particularly those using MediaTek hardware and custom Linux kernels, should be aware of this issue. However, for typical IT infrastructure, cloud environments, and end-user systems across Europe, the risk is negligible. The vulnerability does not affect confidentiality or integrity of data and does not require user interaction or authentication to manifest, but its scope is limited to kernel compilation scenarios rather than runtime exploitation.

The primary mitigation is to apply the patch that explicitly checks for the divide-by-zero condition in pwm_mediatek_config() during kernel compilation. Developers and maintainers compiling custom Linux kernels for MediaTek platforms should ensure they are using updated kernel source code that includes this fix. Avoid compiling kernels with the CONFIG_COMPILE_TEST option enabled while disabling CONFIG_HAVE_CLK, as this combination triggers the vulnerability. For organizations using standard Linux distributions, ensure that kernel updates from trusted vendors are applied promptly, as these distributions will incorporate the fix in their kernel releases. Additionally, maintain rigorous kernel build and testing procedures to detect and prevent unusual configuration combinations that could introduce similar issues. Monitoring kernel build logs for warnings related to objtool or unexpected section ends can also help identify potential problems early. Since no known exploits exist, no runtime mitigations are necessary beyond standard kernel update practices.