CVE-2024-36019 is a vulnerability identified in the Linux kernel's regmap subsystem, specifically within the maple regcache implementation. The issue arises from incorrect indexing of the entry[] array in the regcache_maple_drop() function. Instead of indexing the array by the offset from the base register of the cache block (i.e., max - mas.index), the code incorrectly uses the register address directly. This leads to an out-of-bounds memory access where kernel memory may be copied over the cache contents, causing cache corruption. The vulnerability was not detected by existing regmap KUnit tests because those tests only used register blocks starting at zero, where mas.index equals zero, masking the bug. This flaw could potentially lead to memory corruption within the kernel space, which might be exploited to cause system instability, crashes, or potentially privilege escalation if an attacker can manipulate the cache contents. However, there are no known exploits in the wild at this time, and the vulnerability requires conditions that may limit its exploitation, such as specific kernel configurations or hardware using the maple regmap implementation.

For European organizations, the impact of this vulnerability depends largely on the deployment of Linux systems using the affected kernel versions and the maple regmap cache implementation. Since Linux is widely used across servers, embedded devices, and workstations, any system running a vulnerable kernel could be at risk of kernel memory corruption. This could lead to system crashes, denial of service, or potentially privilege escalation attacks if exploited. Critical infrastructure, cloud service providers, and enterprises relying on Linux-based systems for sensitive operations could face operational disruptions or security breaches. The absence of known exploits reduces immediate risk, but the vulnerability's presence in kernel memory management means that successful exploitation could have severe consequences for confidentiality, integrity, and availability of affected systems. European organizations with embedded Linux devices or custom kernel builds should be particularly vigilant, as these environments may be more likely to use regmap implementations like maple.

Organizations should promptly update their Linux kernels to versions where this vulnerability has been patched. Since the vulnerability stems from a kernel subsystem, applying official kernel patches or upgrading to the latest stable kernel releases that include the fix is the most effective mitigation. For environments where immediate patching is not feasible, organizations should audit their systems to identify usage of the maple regmap cache and assess exposure. Limiting access to vulnerable systems, enforcing strict privilege separation, and monitoring for unusual kernel crashes or memory corruption symptoms can help reduce risk. Additionally, developers and system integrators should enhance their testing frameworks to include regmap tests with non-zero base register offsets to detect similar bugs in the future. Finally, organizations should maintain robust backup and recovery procedures to mitigate potential damage from exploitation attempts.