CVE-2021-40507: Openrisc OR1200 Firmware

Critical severity, CVSS 9.8. EPSS: 0.7% chance of exploitation in the next 30 days.

An issue was discovered in the ALU unit of the OR1200 (aka OpenRISC 1200) processor 2011-09-10 through 2015-11-11. The overflow flag is not being updated correctly for the subtract instruction, which results in an incorrect value in the overflow flag. Any software that relies on this flag may experience corruption in execution.

Affected products

• Openrisc OR1200 Firmware: from 2011-09-10, up to and including 2015-11-11

Published 2023-04-18. Last modified 2026-06-17.