Security readout for executives and security teams
Plain-English summary
This vulnerability affects Huawei’s HW_KEYMASTER component on listed HarmonyOS and EMUI versions. A missing length bounds check can allow specially constructed data to trigger out-of-bounds access. The CVSS score is critical, but the provided sources do not show confirmed active exploitation.
Executive priority
Treat this as high-priority for organizations with Huawei mobile devices or managed endpoints on affected versions. The score is critical and requires prompt patch verification, but urgency should be based on confirmed asset exposure because exploitation evidence is not provided.
Technical view
CVE-2021-46839 is a CWE-125 out-of-bounds access issue in Huawei HW_KEYMASTER caused by missing bounds validation on length. The CVSS 3.1 vector is network-accessible, low complexity, no privileges, no user interaction, unchanged scope, with high confidentiality and integrity impact and no availability impact.
Likely exposure
Exposure is limited to Huawei devices running HarmonyOS 2.0 or EMUI 12.0.0 or 11.0.1, based on the source bundle. The sources do not identify additional products, device models, or fixed build numbers.
Exploitation context
The CVSS vector indicates remote, unauthenticated exploitability in theory. However, the CVE is not listed as KEV in the provided data, and the supplied sources do not provide evidence of exploitation in the wild or public exploit availability.
Researcher notes
The public bundle gives limited technical detail beyond missing bounds checking in HW_KEYMASTER and potential out-of-bounds access. It does not include proof-of-concept detail, fixed versions, affected model lists, or exploit telemetry. Validation should stay focused on version exposure and Huawei advisory mapping.
Mitigation direction
- Identify Huawei devices running the affected HarmonyOS or EMUI versions.
- Review Huawei October 2022 security bulletins for official update guidance.
- Apply Huawei-provided security updates for affected devices when available.
- If updates are unavailable, ask Huawei support for model-specific remediation guidance.
- Avoid relying on unlisted workarounds as permanent mitigation.
Validation and detection
- Inventory Huawei device OS versions and patch levels.
- Compare affected devices against Huawei October 2022 bulletin entries.
- Confirm whether HarmonyOS 2.0 or EMUI 12.0.0/11.0.1 remains present.
- Track remediation status by device model and firmware build.
- Document any unsupported devices requiring vendor escalation.
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-125: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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-2021-46839 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
- 9.1 (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:N
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:N3.95.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.1CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
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.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.