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CVE Record

CVE-2021-39990: The screen lock module has a Stack-based Buffer Overflow vulnerability.Successful exploitation of this vuln...

The screen lock module has a Stack-based Buffer Overflow vulnerability.Successful exploitation of this vulnerability may affect user experience.

CriticalCVSS 9.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

CVE-2021-39990 is a critical stack-based buffer overflow in Huawei HarmonyOS 2.0's screen lock module. The source says successful exploitation may affect user experience, while the CVSS rating indicates potential severe confidentiality, integrity, and availability impact.

Executive priority

Prioritize remediation for any HarmonyOS 2.0 fleet, especially managed or business-critical devices. The severity is critical, but business urgency depends on actual device presence because the source bundle names only HarmonyOS 2.0 and gives limited product detail.

Technical view

The CVE describes CWE-787 memory corruption in the HarmonyOS 2.0 screen lock module. The assigned CVSS 3.1 vector is AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, indicating remote, unauthenticated, low-complexity exposure according to the record.

Likely exposure

Exposure appears limited to Huawei HarmonyOS 2.0 devices containing the vulnerable screen lock module. The bundle does not provide CPEs, device models, affected builds, or fixed versions.

Exploitation context

The provided data does not show CISA KEV listing or active exploitation. No public exploit status is supported by the supplied sources. Treat exploitability indicators as CVSS-based only.

Researcher notes

Evidence is sparse: the CVE identifies a stack-based buffer overflow in the screen lock module, but does not include root cause, affected builds, fixed versions, or exploitation evidence. Avoid assuming broader Huawei product impact without vendor confirmation.

Mitigation direction

  • Review Huawei's November 2021 HarmonyOS security bulletin for vendor guidance.
  • Inventory HarmonyOS 2.0 devices and identify screen-lock-related update status.
  • Apply applicable Huawei security updates where available.
  • Use MDM controls to prioritize remediation for managed HarmonyOS fleets.
  • Escalate to Huawei support if fixed builds are unclear.

Validation and detection

  • Confirm whether any managed devices run HarmonyOS 2.0.
  • Compare device firmware and patch levels with Huawei bulletin guidance.
  • Check vulnerability management tools for CVE-2021-39990 coverage.
  • Track exceptions where device model or fixed version evidence is missing.
  • Monitor Huawei advisories for corrected affected-version details.
Prepared
Confidence
medium
Sources
3

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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-787: 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.

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cve · low confidence lookup

CVE-2021-39990 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
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

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
2Source 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
9.8CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

9.8Critical
CVSS 3.1 vector shape for CVE-2021-39990Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/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
HuaweiHarmonyOS2.0Listed
Weakness

CWE details

CWE-787

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.