CVE-2024-44966 is a vulnerability in the Linux kernel related to the binfmt_flat subsystem, specifically affecting a RISC-V specific variant of the FLAT binary format loader. The issue originated from commit 04d82a6d0881, which introduced a variant that does not allocate space for an obsolete array of shared library pointers. However, the code responsible for initializing this array was not disabled accordingly. As a result, the initialization process corrupts memory by overwriting sizeof(long) bytes immediately before the DATA segment, typically at the end of the TEXT segment. This memory corruption arises because the code attempts to write to a region that was not reserved, leading to potential instability or undefined behavior in the kernel or user-space processes relying on this loader. The fix involves introducing a guard macro, MAX_SHARED_LIBS_UPDATE, which depends on the configuration option CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET. This guard ensures that the shared library pointer region is only initialized if space has been reserved for it, preventing the out-of-bounds write and subsequent corruption. While this vulnerability is specific to the RISC-V architecture variant of the FLAT binary format loader, it affects Linux kernel versions containing the faulty commit. There are no known exploits in the wild at this time, and no CVSS score has been assigned yet. The vulnerability primarily impacts systems running Linux kernels with this specific commit and configuration, particularly those using RISC-V architectures with the binfmt_flat loader enabled.

The potential impact of CVE-2024-44966 on European organizations depends on their deployment of Linux systems using RISC-V architectures and the binfmt_flat loader with the affected configuration. Memory corruption vulnerabilities in the kernel can lead to system instability, crashes, or potentially privilege escalation if exploited by a local attacker. Although no known exploits exist currently, the vulnerability could be leveraged to cause denial of service or, in worst cases, arbitrary code execution within kernel space, compromising confidentiality, integrity, and availability of affected systems. European organizations involved in research, development, or deployment of RISC-V based Linux systems—such as academic institutions, technology companies, or critical infrastructure operators experimenting with emerging architectures—may be at risk. The impact is mitigated by the relatively niche use of RISC-V in production environments compared to x86 or ARM architectures. However, as RISC-V adoption grows, the risk surface expands. Additionally, organizations relying on embedded systems or IoT devices running Linux on RISC-V could face operational disruptions if these devices are vulnerable and exploited. The vulnerability's exploitation requires local access and specific kernel configurations, limiting remote attack vectors but emphasizing the need for internal security controls and patch management.

To mitigate CVE-2024-44966, European organizations should: 1) Identify Linux systems running on RISC-V architectures, particularly those using the binfmt_flat loader with the CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET option enabled. 2) Apply the official Linux kernel patches that introduce the MAX_SHARED_LIBS_UPDATE guard to prevent the memory corruption. This involves updating to kernel versions that include the fix from commit 04d82a6d0881 or later. 3) If immediate patching is not feasible, consider disabling the binfmt_flat loader or the specific FLAT format support on affected systems to reduce exposure. 4) Implement strict access controls and monitoring on systems with local user access to prevent unauthorized exploitation attempts. 5) Conduct thorough testing of kernel updates in controlled environments to ensure stability before wide deployment, especially in production or critical systems. 6) Maintain an inventory of RISC-V Linux deployments and monitor vendor advisories for further updates or related vulnerabilities. 7) Educate system administrators and security teams about the specific nature of this vulnerability to ensure timely response and awareness.