Security readout for executives and security teams
Plain-English summary
CVE-2021-20733 affects asken diet for Android versions v3.0.0 through v4.2.x. A flaw in the app’s custom URL handling could let a remote attacker lure a user into opening an arbitrary website through the app. The sources do not report code execution, data theft, or active exploitation.
Executive priority
Treat this as a targeted mobile-app exposure rather than an enterprise-wide emergency. Prioritize organizations with managed Android fleets or users relying on this app, especially where phishing risk is material.
Technical view
The issue is described as improper authorization in a custom URL scheme handler. The documented outcome is attacker-directed navigation to an arbitrary website via the vulnerable Android app. No CVSS score, CWE mapping, patch version, or exploit details are provided in the supplied sources.
Likely exposure
Exposure is limited to Android devices with あすけんダイエット / asken diet versions v3.0.0 to v4.2.x installed.
Exploitation context
The public description indicates remote exploitation requires leading a user to interact with the vulnerable app or URL flow. CISA KEV status is false, and no cited source confirms active exploitation.
Researcher notes
Evidence is sparse. The source bundle identifies the vulnerable product and impact, but does not provide CVSS, CWE, affected Android OS versions, fixed version, proof of exploitation, or technical root-cause detail.
Mitigation direction
- Inventory Android devices for asken diet versions v3.0.0 through v4.2.x.
- Check asken and JVN guidance for a fixed or recommended version.
- Update to a vendor-supported fixed version if one is available.
- Remove the vulnerable app where business use is unnecessary.
- Warn users not to trust unexpected app-opening links.
Validation and detection
- Confirm installed Android app versions through MDM or device inventory.
- Verify no managed devices retain versions v3.0.0 through v4.2.x.
- Review vendor and JVN notices for remediation status.
- Check mobile security telemetry for unexpected URL-opening 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.
CVE-2021-20733 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.asken.jp/s/login/?to=/informationCVE reference · x_refsource_MISC
- https://jvn.jp/en/jp/JVN38034268/index.htmlCVE reference · x_refsource_MISC
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.