CVE-2025-51678 in PicoRV32
Summary
by MITRE • 07/17/2026
An issue was discovered in RISC-V PicoRV32 commit 87c89a. A mismatch in the PCPI INSN and memory address can lead to unexpected behavior.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 07/17/2026
The vulnerability in RISC-V PicoRV32 represents a critical architectural flaw that undermines the processor's instruction execution integrity. This issue stems from a fundamental mismatch between the Program Counter Peripheral Interface (PCPI) instruction field and the actual memory addressing mechanism within the processor core. The problem manifests when the PCPI INSN field fails to accurately reflect the memory address where instructions are fetched and executed, creating a disconnect that can lead to unpredictable system behavior.
This technical flaw operates at the intersection of hardware design and instruction processing, where the processor's ability to maintain proper program flow becomes compromised. The mismatch occurs during instruction fetch cycles when the PCPI interface, which is responsible for communicating instruction addresses to peripheral components, provides incorrect information relative to the actual memory locations being accessed. This discrepancy creates opportunities for instruction misalignment that can cascade into broader system instability.
The operational impact of this vulnerability extends beyond simple instruction execution errors and can potentially enable privilege escalation attacks or arbitrary code execution. When the PCPI INSN field does not properly align with memory addresses, malicious actors could exploit this inconsistency to manipulate program flow, bypass security checks, or inject unauthorized instructions into the execution pipeline. The vulnerability particularly affects systems relying on PicoRV32 for embedded applications where predictable instruction behavior is essential for maintaining system integrity and security.
From a cybersecurity perspective, this vulnerability aligns with CWE-122 which addresses buffer overflow conditions in memory management, and may also relate to CWE-129 which deals with insufficient input validation. The issue demonstrates how low-level hardware design flaws can create foundational security weaknesses that propagate through entire systems. In the context of ATT&CK framework, this vulnerability could be categorized under TA0004 Privilege Escalation and TA0005 Defense Evasion, as it enables attackers to manipulate instruction execution and potentially bypass system protections.
Mitigation strategies should focus on implementing robust instruction validation mechanisms and ensuring proper synchronization between PCPI interface components and memory addressing units. Hardware updates to correct the address mapping logic would provide the most effective solution, while software-level workarounds involving instruction set validation routines could serve as interim measures. Organizations deploying PicoRV32 processors must conduct thorough security assessments to identify potential exploitation paths and implement monitoring systems to detect anomalous instruction execution patterns that might indicate exploitation attempts.