CVE-2021-20834Network attack vector

Arbitrary website navigation via unrestricted custom URL handler

Published Oct 13, 2021 · Updated Aug 3, 2024

Improper authorization in Nike App before Android 2.177 and iOS 2.177.1 allows remote attackers to open arbitrary websites. The custom URL scheme handler accepts requests from arbitrary applications and opens the requested URL without restricting the caller. Exploitation requires user interaction with attacker-supplied content and can direct the user to a phishing or other attacker-chosen site.

CVSS severity4.3
Medium
EPSS probability1.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in Nike App before Android 2.177 and iOS 2.177.1 allows remote attackers to open arbitrary websites. The custom URL scheme handler accepts requests from arbitrary applications and opens the requested URL without restricting the caller. Exploitation requires user interaction with attacker-supplied content and can direct the user to a phishing or other attacker-chosen site.

The record

CVE
CVE-2021-20834
Published
Oct 13, 2021
Updated
Aug 3, 2024
Vendor
Nike, Inc.
Product
Nike App
Classifications
CWE-862, CWE-939, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 13, 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=Nike App for Android versions prior to 2.177 and Nike App for iOS versions prior to 2.177.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Nike, Inc. · Nike Appversion=Nike App for Android versions prior to 2.177 and Nike App for iOS versions prior to 2.177.1

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3JPCERT/CCAV:N/AC:M/Au:N/C:N/I:P/A:N
4.3JPCERT/CCCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
5.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
CWE-939Improper Authorization in Handler for Custom URL Scheme
T1204.001Malicious Link

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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