What is CVE-2021-20747?

CVE-2021-20747 is a medium-severity vulnerability in Retty, classified under Missing Authorization. CVSS score: 4.3/10. Published 2021-07-14.

How severe is CVE-2021-20747?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Auth bypass in Retty

CVE-2021-20747

Improper authorization in handler for custom URL scheme vulnerability in Retty App for Android versions prior to 4.8.13 and Retty App for iOS versions prior to 4.11.14 allows a remote attacker to lead a user to access an arbitrary website via the vulnerable App.

Vulnerability class: Broken Access Control

Published 2021-07-14 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.010 (61.6th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 62nd percentile — 61.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Retty
Retty Inc. App — versions Retty App for Android versions prior to 4.8.13 and Retty App for iOS versions prior to 4.11.14

Weakness classification (CWE)

CWE-862 — Missing Authorization

References

drive.google.com/file/d/1PBYqIsK8QxEEhGJ4SEgpY7iZw3RTTDho/view (Third Party Advisory)
jvn.jp/en/jp/JVN26891339/index.html (Third Party Advisory)

Frequently asked questions

What is CVE-2021-20747?: CVE-2021-20747 is a medium-severity vulnerability in Retty, classified under Missing Authorization. CVSS score: 4.3/10. Published 2021-07-14.
How severe is CVE-2021-20747?: Medium severity. CVSS v3 base score is 4.3 out of 10.