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CVE Record

CVE-2021-41612: An issue was discovered in the ALU unit of the OpenRISC mor1kx processor.

An issue was discovered in the ALU unit of the OpenRISC mor1kx processor. The carry flag is not being updated correctly for the subtract instruction, which results in an incorrect value of the carry flag. Any software that relies on this flag may experience corruption in execution.

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2021-41612 is a processor logic flaw in the OpenRISC mor1kx ALU. A subtract instruction may leave the carry flag wrong, so software depending on that flag can make incorrect decisions and corrupt execution. This matters mainly to organizations using mor1kx in embedded, FPGA, or custom processor designs.

Executive priority

Prioritize if your products or infrastructure use OpenRISC mor1kx, especially in deployed embedded or FPGA systems. For organizations without mor1kx exposure, urgency is low despite the high CVSS score. The main task is exposure confirmation, then supplier or upstream remediation tracking.

Technical view

The CVE describes incorrect carry-flag updating for subtract instructions in the OpenRISC mor1kx ALU. The listed CVSS 3.1 score is 8.8 with high confidentiality, integrity, and availability impact. The public bundle does not provide specific affected versions, CPEs, CWE mapping, patch status, or confirmed exploitation.

Likely exposure

Exposure is likely limited to systems, firmware, or hardware designs that include the OpenRISC mor1kx processor core. The CVE record lists affected vendor, product, and versions as unavailable, so asset owners must validate use through hardware BOMs, HDL sources, and supplier records.

Exploitation context

No active exploitation is supported by the provided sources, and the CVE is not marked KEV. The issue is a CPU correctness fault rather than a conventional application bug; business impact depends on whether deployed software relies on the subtract carry flag for control flow, arithmetic, or security-sensitive logic.

Researcher notes

The useful research path is verification, not weaponization: identify affected mor1kx revisions, reproduce the carry-flag mismatch in a controlled testbench, and map software impact. The source bundle does not name a fixed release, affected version range, or public exploitation evidence.

Mitigation direction

  • Inventory hardware and firmware projects for OpenRISC mor1kx usage.
  • Review upstream mor1kx issue and project guidance for corrected HDL or advisories.
  • Ask suppliers whether delivered SoCs, FPGA images, or IP blocks include affected mor1kx logic.
  • Add regression coverage for subtract carry-flag behavior before releasing hardware images.
  • Avoid security-critical deployment until corrected behavior is verified.

Validation and detection

  • Confirm mor1kx presence in HDL repositories, FPGA projects, SoC manifests, or vendor documentation.
  • Run controlled ALU conformance tests covering subtract carry-flag behavior.
  • Review firmware for branches, arithmetic, or multiword operations depending on carry after subtract.
  • Check CI or hardware verification suites for regression tests tied to this defect.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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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CVE-2021-41612 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Official CVE source material

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.

1CVSS vectors
0Timeline events
0ADP providers
3Source links

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
8.8CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

8.8High
CVSS 3.1 vector shape for CVE-2021-41612Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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