CVE-2025-56301
📋 TL;DR
This vulnerability in Rocket-Chip's CSR logic allows attackers to corrupt exception handling and privilege state transitions by triggering an exception during MRET instruction execution. This can lead to privilege escalation or system instability. It affects systems using vulnerable versions of the Rocket-Chip RISC-V processor implementation.
💻 Affected Systems
- Chipsalliance Rocket-Chip RISC-V processor implementation
📦 What is this software?
Rocket Chip by Chipsalliance
⚠️ Risk & Real-World Impact
Worst Case
Privilege escalation from user mode to machine mode, allowing complete system compromise and arbitrary code execution at highest privilege level.
Likely Case
System instability, crashes, or privilege escalation in multi-tenant environments where untrusted code runs on vulnerable hardware.
If Mitigated
Limited impact if systems run only trusted code or have additional hardware security mechanisms.
🎯 Exploit Status
Exploitation requires detailed knowledge of RISC-V architecture and ability to execute arbitrary code on target system.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check latest Rocket-Chip repository commits after 2025-01-29
Vendor Advisory: https://github.com/chipsalliance/rocket-chip
Restart Required: Yes
Instructions:
1. Update to latest Rocket-Chip repository version. 2. Recompile and redeploy hardware designs. 3. Update firmware/software to use patched hardware.
🔧 Temporary Workarounds
Avoid MRET in machine mode
allModify software to avoid using MRET instruction in machine mode where possible
N/A - Requires code modifications
Exception handler hardening
allImplement additional checks in exception handlers to detect corrupted state
N/A - Requires firmware/software modifications
🧯 If You Can't Patch
- Isolate systems with vulnerable hardware from untrusted networks and users
- Implement strict access controls and monitoring on systems using vulnerable hardware
🔍 How to Verify
Check if Vulnerable:
Check Rocket-Chip commit hash: git log --oneline | grep f517abbf41abb65cea37421d3559f9739efd00a9Check Version:
git log --oneline -1Verify Fix Applied:
Verify using updated commit: git log --oneline | head -20 to confirm newer commits are present📡 Detection & Monitoring
Log Indicators:
- Multiple simultaneous exception handling events
- Unexpected privilege mode changes
- System crashes during exception handling
Network Indicators:
- N/A - Local hardware vulnerability
SIEM Query:
Search for: 'exception fault during MRET' OR 'privilege escalation attempt' OR 'CSR corruption'🔗 References
- https://github.com/chipsalliance/rocket-chip
- https://github.com/chipsalliance/rocket-chip/blob/f517abbf41abb65cea37421d3559f9739efd00a9/src/main/scala/rocket/CSR.scala
- https://github.com/chipsalliance/rocket-chip/blob/master/src/main/scala/rocket/CSR.scala
- https://github.com/heyfenny/Vulnerability_disclosure/blob/main/RISCV/Rocket-chip/CVE-2025-56301/details.md
- https://lf-riscv.atlassian.net/wiki/spaces/HOME/pages/16154769/RISC-V+Technical+Specifications#ISA-Specifications
