Security readout for executives and security teams
Plain-English summary
CVE-2021-40506 is a logic flaw in the OR1200/OpenRISC 1200 processor ALU. Some multiply-related instructions may leave the overflow flag wrong, so software depending on that flag can make incorrect decisions and corrupt execution.
Executive priority
Prioritize assessment if your products or lab platforms embed OR1200. The CVSS is critical, but business urgency is highest for deployed hardware designs where incorrect arithmetic flags can affect integrity or availability.
Technical view
The ALU overflow flag is not updated for the msb and mac instructions in OR1200 code dated 2011-09-10 through 2015-11-11. The CVE record rates this critical, but affected vendor/product metadata is incomplete.
Likely exposure
Exposure is likely limited to systems, FPGA designs, simulators, or SoC projects embedding OR1200/OpenRISC 1200 from the affected source window or downstream forks.
Exploitation context
The source bundle does not show KEV listing or active exploitation. Practical impact depends on whether deployed software relies on the overflow flag after affected instructions.
Researcher notes
CWE metadata lists CWE-287, but the described issue is processor ALU flag correctness. Treat product scope cautiously because the source bundle lists affected vendor and product as n/a.
Mitigation direction
- Inventory SoCs, FPGA bitstreams, simulators, and forks that include OR1200/OpenRISC 1200.
- Check whether the ALU source includes the upstream fix commit or equivalent changes.
- Rebuild and revalidate hardware images from fixed HDL where OR1200 is present.
- Consult the OpenRISC project or downstream vendor guidance before production deployment.
Validation and detection
- Compare local OR1200 source history against the affected 2011-09-10 to 2015-11-11 window.
- Review ALU logic for overflow flag handling on msb and mac instructions.
- Run regression tests covering overflow flag behavior after affected instructions.
- Identify software paths that branch, trap, or validate data using the overflow flag.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-287: Credential and account abuse lookup
Authentication and credential weaknesses can make valid-account abuse and credential telemetry useful review starting points. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-40506 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Authentication
Improper Authentication represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.