BaseFortify

Publication date: 2025-09-30

Last updated on: 2025-10-17

Assigner: MITRE

Description

An issue was discovered in Chipsalliance Rocket-Chip commit f517abbf41abb65cea37421d3559f9739efd00a9 (2025-01-29) allowing attackers to corrupt exception handling and privilege state transitions via a flawed interaction between exception handling and MRET return mechanisms in the CSR logic when an exception is triggered during MRET execution. The Control and Status Register (CSR) logic has a flawed interaction between exception handling and exception return (MRET) mechanisms which can cause faulty trap behavior. When the MRET instruction is executed in machine mode without being in an exception state, an Instruction Access Fault may be triggered. This results in both the exception handling logic and the exception return logic activating simultaneously, leading to conflicting updates to the control and status registers.

CVSS Scores

EPSS Scores

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Meta Information

Published

2025-09-30

Last Modified

2025-10-17

Generated

2026-07-06

AI Q&A

2025-09-30

EPSS Evaluated

2026-07-05

NVD

CVE-2025-56301

Affected Vendors & Products

Vendor	Product	Version / Range
chipsalliance	rocket-chip	2025-01-29

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-1281	Specific combinations of processor instructions lead to undesirable behavior such as locking the processor until a hard reset performed.

Attack-Flow Graph

Executive Summary

This vulnerability exists in the Chipsalliance Rocket-Chip's Control and Status Register (CSR) logic. It involves a flawed interaction between exception handling and the MRET (machine return) instruction. Specifically, when an exception is triggered during the execution of the MRET instruction, the exception handling and exception return mechanisms activate simultaneously, causing conflicting updates to the CSR. This can corrupt exception handling and privilege state transitions, leading to faulty trap behavior and potentially triggering an Instruction Access Fault when MRET is executed in machine mode outside of an exception state.

Impact Analysis

The vulnerability can lead to corruption of exception handling and privilege state transitions in the affected system. This may cause unexpected or faulty trap behavior, potentially destabilizing the system or allowing attackers to interfere with the normal control flow and privilege levels. Such corruption could be exploited to bypass security mechanisms or cause denial of service by triggering faults during critical operations.

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