CVE-2024-53105 is a vulnerability identified in the Linux kernel's memory management subsystem, specifically related to the handling of mlocked pages during page freeing operations. The issue arises because the mlocked flag clearance was not properly moved into the free_pages_prepare() function, leading to a scenario where a page could be freed while still marked as mlocked. This causes a 'bad page state' error, as detected by Syzbot, a kernel fuzzing tool. The vulnerability manifests as a kernel BUG triggered by freeing a page with the mlocked flag still set, which violates internal kernel consistency checks (PAGE_FLAGS_CHECK_AT_FREE). The detailed kernel stack traces indicate that the problem occurs during page allocation and freeing routines, particularly involving the functions free_pages_prepare(), free_unref_folios(), and related memory management code paths. The vulnerability affects Linux kernel version 6.12.0-rc6 and potentially other versions with similar memory management code. It is triggered in contexts involving kernel virtual machine (KVM) operations, as evidenced by the stack trace referencing kvm_create_vm and kvm_destroy_vm functions. The root cause is a race or logic error in clearing the mlocked flag during page freeing, which can lead to kernel instability or crashes due to corrupted page state. No known exploits are reported in the wild yet, and no CVSS score has been assigned. The vulnerability was publicly disclosed on December 2, 2024, and is considered a kernel-level memory management bug that could impact system stability and security.

For European organizations, this vulnerability poses a risk primarily to systems running vulnerable Linux kernel versions, especially those utilizing KVM virtualization technology. The impact includes potential kernel panics or system crashes, leading to denial of service (DoS) conditions. In environments where Linux hosts critical infrastructure, cloud services, or virtualized workloads, such instability can disrupt business operations, cause data loss, or degrade service availability. Although no direct remote code execution or privilege escalation is indicated, the kernel crash could be leveraged by attackers to cause persistent denial of service or to facilitate further attacks by destabilizing the system. Organizations relying on Linux-based servers, particularly those running on Google Cloud Platform (as the hardware trace indicates Google Compute Engine), may face operational disruptions. The vulnerability affects confidentiality and availability due to system crashes and potential data corruption. Given the kernel-level nature, the impact scope is broad across Linux distributions using the affected kernel versions. European sectors with high reliance on Linux virtualization, such as finance, telecommunications, and cloud service providers, are particularly at risk.

1. Immediate patching: Apply the official Linux kernel patches that address the mlocked flag clearance issue in free_pages_prepare(). Monitor Linux kernel mailing lists and vendor advisories for updated stable kernel releases incorporating this fix. 2. Kernel version management: Avoid deploying or running vulnerable kernel versions (e.g., 6.12.0-rc6) in production environments until patched. Use Long Term Support (LTS) kernels where possible. 3. Virtualization hardening: For systems using KVM, consider isolating critical workloads and limiting exposure to untrusted guests or processes that might trigger the vulnerability. 4. Monitoring and alerting: Implement kernel crash monitoring and alerting to detect early signs of this vulnerability being triggered. 5. Controlled testing: Conduct controlled testing of the patch in staging environments to ensure stability before production rollout. 6. Limit privileged access: Restrict access to kernel-level operations and KVM device interfaces to trusted administrators to reduce risk of exploitation. 7. Backup and recovery: Maintain up-to-date backups and recovery plans to mitigate impact of potential system crashes caused by this vulnerability.