CVE-2021-20873

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-12-28 · updated 2026-06-17
Weakness: CWE-862

Description

Yappli is an application development platform which provides the function to access a requested URL using Custom URL Scheme. When Android apps are developed with Yappli versions since v7.3.6 and prior to v9.30.0, they are vulnerable to improper authorization in Custom URL Scheme handler, and may be directed to unintended sites via a specially crafted URL.

Affected products

Yappli, Inc. Yappli: from 7.3.6 before 9.30.0 — fixed in 9.30.0

How to fix

Upgrade to a fixed version: Yappli, Inc. Yappli 9.30.0. Check the vendor advisory for mitigations.

References

https://jvn.jp/en/jp/JVN66422035/index.html
https://support.yappli.co.jp/hc/ja/articles/4410249902745
https://jvn.jp/en/jp/JVN66422035/index.html
https://support.yappli.co.jp/hc/ja/articles/4410249902745

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