CVE-2021-20693

Phishing redirects via unrestricted custom URL scheme

Published Apr 26, 2021 · Updated Aug 3, 2024

Improper access control in Rakuten Gurunavi App 10.0.14 and earlier for Android and 11.2.3 and earlier for iOS allows attackers to redirect users. Its custom URL scheme accepts a requested URL from any installed app without authorizing the caller, then opens that URL. A malicious app and user interaction are required; successful exploitation opens an attacker-chosen website that can impersonate a trusted site.

CVSS severity3.3
Low
EPSS probability1.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Rakuten Gurunavi App 10.0.14 and earlier for Android and 11.2.3 and earlier for iOS allows attackers to redirect users. Its custom URL scheme accepts a requested URL from any installed app without authorizing the caller, then opens that URL. A malicious app and user interaction are required; successful exploitation opens an attacker-chosen website that can impersonate a trusted site.

The record

CVE
CVE-2021-20693
Published
Apr 26, 2021
Updated
Aug 3, 2024
Vendor
Gurunavi, Inc.
Product
Rakuten Gurunavi App
Classifications
CWE-284, CWE-862
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=for Android ver.10.0.10 and earlier and for iOS ver.11.1.2 and earlier

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Gurunavi, Inc. · Rakuten Gurunavi Appversion=for Android ver.10.0.10 and earlier and for iOS ver.11.1.2 and earlier

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:P/A:N
4.3JPCERT/CCAV:N/AC:M/Au:N/C:N/I:P/A:N
3.3JPCERT/CCCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
CWE-862Missing Authorization

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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