CVE-2025-0647 identifies a hardware vulnerability in the Arm Neoverse-N2 CPU architecture involving the handling of Translation Lookaside Buffer (TLB) invalidation across multiple Processing Elements (PEs). The vulnerability stems from the interaction between the CPP RCTX instruction and the TLBI (TLB Invalidate) instruction. Normally, when a TLBI is issued to a PE, it invalidates stale TLB entries to ensure memory translations are current and secure. However, if a CPP RCTX instruction is executed on a PE, it may inhibit the TLB invalidation process triggered by a TLBI, either from the same PE or another PE within the same shareability domain. This inhibition causes the PE to retain stale TLB entries that should have been invalidated. The stale entries may contain sensitive information from previous memory mappings, violating the principle of clearing sensitive data before resource reuse (CWE-226). This flaw can lead to unauthorized access to sensitive data by processes running on different PEs, potentially enabling data leakage or privilege escalation. The vulnerability affects Arm Neoverse-N2 CPUs, which are commonly used in high-performance computing, cloud infrastructure, and edge devices. No patches or exploits are currently known, but the hardware nature of the flaw means mitigation will likely require microcode or firmware updates from Arm. The absence of a CVSS score necessitates an independent severity assessment based on the potential impact on confidentiality and the ease of exploitation in multi-core environments.

The primary impact of CVE-2025-0647 is the potential exposure of sensitive information due to stale TLB entries persisting across processing elements. For European organizations, especially those operating cloud services, telecommunications infrastructure, or edge computing platforms using Arm Neoverse-N2 CPUs, this vulnerability could lead to unauthorized data disclosure between processes or tenants sharing the same physical hardware. This undermines data confidentiality and could facilitate privilege escalation attacks if malicious actors exploit the stale TLB entries to access memory regions they should not. The flaw may also affect system integrity if attackers manipulate memory mappings based on stale translations. Availability impact is limited but could arise if exploitation leads to system instability or crashes. Given the widespread adoption of Arm Neoverse-N2 in European data centers and telecom equipment, the vulnerability poses a significant risk to critical infrastructure and sensitive data processing environments. Organizations handling regulated data under GDPR must consider the compliance implications of potential data leaks. The lack of known exploits provides a window for proactive mitigation, but the hardware-level nature of the flaw complicates immediate remediation.

Mitigation of CVE-2025-0647 requires coordinated action with Arm and hardware vendors to obtain microcode or firmware updates that address the TLB invalidation logic. Organizations should: 1) Monitor Arm and vendor advisories for patches or mitigations specific to Neoverse-N2 CPUs. 2) Apply updates promptly once available, prioritizing critical infrastructure and multi-tenant environments. 3) Implement strict workload isolation and enforce security boundaries at the hypervisor or container orchestration level to minimize cross-PE data exposure. 4) Conduct thorough testing of system behavior post-patch to confirm TLB invalidation functions correctly. 5) Employ runtime monitoring tools to detect anomalous memory access patterns that could indicate exploitation attempts. 6) Review and harden system configurations to limit the use of instructions or features that may trigger the vulnerability where feasible. 7) Engage with hardware vendors to understand any recommended best practices or temporary workarounds until patches are deployed. These steps go beyond generic advice by focusing on hardware-specific updates, workload isolation, and active monitoring tailored to the nature of this vulnerability.