CVE-2024-23850 is a vulnerability identified in the Linux kernel's Btrfs filesystem code, specifically within the btrfs_get_root_ref function in fs/btrfs/disk-io.c, present through kernel version 6.7.1. The issue stems from a timing flaw where a subvolume can be read prematurely immediately after its root item is inserted during subvolume creation. This premature access triggers an assertion failure, causing the kernel to crash. The vulnerability is classified under CWE-617 (Reachable Assertion), indicating that an assertion intended to validate internal state can be triggered by crafted input or timing conditions. The impact is a denial of service due to kernel panic, affecting system availability. The CVSS v3.1 score is 5.5 (medium), with attack vector local (AV:L), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), unchanged scope (S:U), and no confidentiality or integrity impact (C:N/I:N), but high availability impact (A:H). There are no known exploits in the wild yet, and no patches are linked at the time of publication, indicating that mitigation relies on forthcoming kernel updates. The vulnerability requires local access and privileges to exploit, limiting remote exploitation but posing risks in multi-user or shared environments where untrusted users can create or manipulate Btrfs subvolumes. The flaw can cause system instability and service interruptions, particularly in environments heavily reliant on Btrfs for storage management.

For European organizations, the primary impact of CVE-2024-23850 is denial of service through kernel crashes on Linux systems using Btrfs. This can disrupt critical services, especially in data centers, cloud providers, and enterprises that utilize Btrfs for its advanced filesystem features such as snapshots and subvolumes. The vulnerability does not compromise data confidentiality or integrity but affects availability, potentially leading to downtime and operational disruption. Organizations with multi-tenant environments or shared systems are at higher risk if untrusted users can create subvolumes. The medium severity reflects the need for timely patching to maintain service continuity. Given the widespread use of Linux in European infrastructure, including government, finance, and telecommunications sectors, the vulnerability could impact business-critical systems if exploited or triggered inadvertently.

1. Monitor Linux kernel updates and apply patches addressing CVE-2024-23850 promptly once released. 2. Restrict local user privileges to prevent untrusted users from creating or manipulating Btrfs subvolumes. 3. Implement strict access controls and auditing on systems using Btrfs to detect unusual subvolume creation or modification activities. 4. Consider temporarily avoiding Btrfs subvolume creation or usage in environments where local privilege separation is weak until patched. 5. Employ kernel crash monitoring and automated recovery mechanisms to minimize downtime in case of assertion failures. 6. For critical systems, evaluate alternative filesystems or configurations that do not expose this vulnerability until a fix is applied. 7. Educate system administrators about the vulnerability to ensure awareness and readiness to respond to potential incidents.