What is CVE-2021-20733?

CVE-2021-20733 is a medium-severity vulnerability in Asken, classified under Missing Authorization. CVSS score: 6.1/10. Published 2021-06-22.

How severe is CVE-2021-20733?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Auth bypass in Asken

CVE-2021-20733

Improper authorization in handler for custom URL scheme vulnerability in あすけんダイエット (asken diet) for Android versions from v.3.0.0 to v.4.2.x allows a remote attacker to lead a user to access an arbitrary website via the vulnerable App.

Vulnerability class: Broken Access Control

Published 2021-06-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.008 (55.7th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 55.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Asken
Asken Inc. あすけんダイエット (Asken Diet) For Android — versions versions from v.3.0.0 to v.4.2.x

Weakness classification (CWE)

CWE-862 — Missing Authorization

References

www.asken.jp/s/login/ (Permissions Required, Vendor Advisory)
jvn.jp/en/jp/JVN38034268/index.html (Third Party Advisory)

Frequently asked questions

What is CVE-2021-20733?: CVE-2021-20733 is a medium-severity vulnerability in Asken, classified under Missing Authorization. CVSS score: 6.1/10. Published 2021-06-22.
How severe is CVE-2021-20733?: Medium severity. CVSS v3 base score is 6.1 out of 10.