CVE-2025-56301: An issue was discovered in Chipsalliance Rocket-Chip commit f517abbf41abb65cea37421d3559f9739efd00a9 (2025-01-29) allowing attackers to corrupt exception handli

An issue was discovered in Chipsalliance Rocket-Chip commit f517abbf41abb65cea37421d3559f9739efd00a9 (2025-01-29) allowing attackers to corrupt exception handli

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.

Description from the National Vulnerability Database, published by MITRE

What it means for a small business

If your business uses Rocket-chip, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.64%, higher than 50% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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