Security readout for executives and security teams
Plain-English summary
CVE-2021-40507 is a hardware logic flaw in the OpenRISC OR1200 ALU. A subtract operation can leave the overflow flag wrong, so software that trusts that flag may make incorrect decisions and corrupt execution. Business urgency depends on whether OR1200-based cores are actually present in products or infrastructure.
Executive priority
Treat as critical for any product line or operational technology using OR1200-derived processor logic. For organizations without OR1200 exposure, priority is low after documented inventory confirmation.
Technical view
The source describes incorrect overflow flag handling for subtract instructions in OR1200 revisions dated 2011-09-10 through 2015-11-11. The stated impact is corruption in software execution when code relies on the overflow flag. The CVSS score is 9.8, but affected vendor/product metadata is incomplete.
Likely exposure
Exposure is most likely in embedded, FPGA, research, or product designs that incorporated OR1200/OpenRISC 1200 RTL from the named date range. Generic enterprise servers, desktops, and cloud workloads are not shown as affected by the provided sources.
Exploitation context
The source bundle does not show CISA KEV listing or public active exploitation. The referenced TAMU THEHuzz page suggests discovery through hardware fuzzing research, but the bundle does not provide weaponized exploitation details or deployment prevalence.
Researcher notes
The CWE value in the bundle is CWE-287, which does not clearly match the described ALU flag behavior. Affected product fields are listed as n/a, so asset confirmation and source-level provenance are central to reliable triage.
Mitigation direction
- Inventory products, FPGA images, and SoC designs for OR1200/OpenRISC 1200 usage.
- Compare OR1200 RTL provenance against the 2011-09-10 through 2015-11-11 affected range.
- Review the upstream OR1200 commit reference for the corrective change.
- Update integrated RTL or downstream builds to a revision containing the correction where feasible.
- For fixed silicon, request vendor or integrator guidance on compensating controls.
Validation and detection
- Confirm whether any deployed component includes OR1200 rather than assuming exposure from CVSS alone.
- Review RTL history, manifests, SBOMs, or vendor attestations for OR1200 commit provenance.
- Check arithmetic/overflow-dependent software paths for reliance on the subtract overflow flag.
- Validate patched RTL or firmware using regression tests that cover subtract overflow behavior.
Public sources used
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
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-2021-40507 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.