Execution corruption via incorrect subtract overflow flag
Published Apr 18, 2023 · Updated Feb 6, 2025
Incorrect overflow handling in OpenRISC OR1200 firmware 2011-09-10 through 2015-11-11 allows attackers to corrupt execution. The ALU in rtl/verilog/or1200_alu.v computes signed overflow incorrectly for certain subtract operands and writes the wrong value to the status-register overflow flag. Attackers must cause software to execute an affected subtraction and then rely on that flag; the documented consequence is corrupted program execution.
Summary
What happened
Incorrect overflow handling in OpenRISC OR1200 firmware 2011-09-10 through 2015-11-11 allows attackers to corrupt execution. The ALU in rtl/verilog/or1200_alu.v computes signed overflow incorrectly for certain subtract operands and writes the wrong value to the status-register overflow flag. Attackers must cause software to execute an affected subtraction and then rely on that flag; the documented consequence is corrupted program execution.
The record
- CVE
- CVE-2021-40507
- Published
- Apr 18, 2023
- Updated
- Feb 6, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-287
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 18, 2023CVE publishedPublication date reported by the CVE source.
- Feb 6, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
Affected products and versions are unavailable in this record.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- TheHuzz B10 triggering inputproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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