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CWE-939

Improper Authorization in Handler for Custom URL Scheme

BaseIncompleteSimple32 CVEs
The product uses a handler for a custom URL scheme, but it does not properly restrict which actors can invoke the handler using the scheme.

Extended description

Mobile platforms and other architectures allow the use of custom URL schemes to facilitate communication between applications. In the case of iOS, this is the only method to do inter-application communication. The implementation is at the developer's discretion which may open security flaws in the application. An example could be potentially dangerous functionality such as modifying files through a custom URL scheme.

Common consequences1

  • Access ControlOtherGain Privileges or Assume IdentityVaries by ContextBypass Protection Mechanism

    An attacker can access any functionality that is inadvertently accessible to the source.

Potential mitigations1

  1. Architecture and Design

    Utilize a user prompt pop-up to authorize potentially harmful actions such as those modifying data or dealing with sensitive information. When designing functionality of actions in the URL scheme, consider whether the action should be accessible to all mobile applications, or if an allowlist of applications to interface with is appropriate.

Relationships2

CVEs referencing this CWE32

CVEDescriptionSeverityEPSSFlagsModified
CVE-2020-11000

GreenBrowser before version 1.2 has a vulnerability where apps that rely on URL Parsing to verify that a given URL is pointing to a trust server may be susceptible to many different ways to get URL parsing and verification wrong, which allows an attacker to circumvent the access control. This problem has been patched in version 1.2.

MEDIUM6.5
1.24%p69
2026-06-17
CVE-2021-31384

Due to a Missing Authorization weakness and Insufficient Granularity of Access Control in a specific device configuration, a vulnerability exists in Juniper Networks Junos OS on SRX Series whereby an attacker who attempts to access J-Web administrative interfaces can successfully do so from any device interface regardless of the web-management configuration and filter rules which may otherwise protect access to J-Web. This issue affects: Juniper Networks Junos OS SRX Series 20.4 version 20.4R1 and later versions prior to 20.4R2-S1, 20.4R3; 21.1 versions prior to 21.1R1-S1, 21.1R2. This issue does not affect Juniper Networks Junos OS versions prior to 20.4R1.

CRITICAL10.0
1.16%p67
2026-06-17
CVE-2022-20736

A vulnerability in the web-based management interface of Cisco AppDynamics Controller Software could allow an unauthenticated, remote attacker to access a configuration file and the login page for an administrative console that they would not normally have authorization to access. This vulnerability is due to improper authorization checking for HTTP requests that are submitted to the affected web-based management interface. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected instance of AppDynamics Controller. A successful exploit could allow the attacker to access the login page for an administrative console. AppDynamics has released software updates that address this vulnerability.

MEDIUM5.3
1.06%p64
2026-06-17
CVE-2023-43582

Improper authorization in some Zoom clients may allow an authorized user to conduct an escalation of privilege via network access.

HIGH8.8
0.66%p51
2026-06-17
CVE-2026-26123

Cwe is not in rca categories in Microsoft Authenticator allows an unauthorized attacker to disclose information locally.

MEDIUM5.5
0.61%p49
2026-06-19
CVE-2026-21075

Improper authorization in handler for custom URL scheme in My Galaxy prior to version 6.3 allows remote attackers to access sensitive information.

NONE
0.49%p42
2026-10-23
CVE-2024-33606

An attacker could retrieve sensitive files (medical images) as well as plant new medical images or overwrite existing medical images on a MicroDicom DICOM Viewer system. User interaction is required to exploit this vulnerability.

HIGH8.8
0.46%p40
2026-06-17
CVE-2026-35394

Mobile Next is an MCP server for mobile development and automation. Prior to 0.0.50, the mobile_open_url tool in mobile-mcp passes user-supplied URLs directly to Android's intent system without any scheme validation, allowing execution of arbitrary Android intents, including USSD codes, phone calls, SMS messages, and content provider access. This vulnerability is fixed in 0.0.50.

HIGH8.8
0.39%p32
2026-07-24
CVE-2026-59717

Home Assistant is open source home automation software focused on local control and privacy. Prior to 2026.6.1, the Android Companion app is vulnerable to an open redirect. The app passes the URL fragment from a homeassistant://invite deep link into the onboarding flow without ever displaying the destination hostname. Because no screen in the invitation or onboarding flow shows the parsed server URL before onboarding commits to it, a victim has no way to distinguish a legitimate invite from a malicious one. An attacker can craft an invite so that a single tap on the legitimate-looking "Connect to my Home Assistant server" button opens their /auth/authorize endpoint in the URL-less onboarding WebView, presenting a look-alike login page that captures the victim's credentials. Since invitations are intended to onboard brand-new users, targets are especially unlikely to notice the substitution. This issue is fixed in version 2026.6.1.

MEDIUM4.3
0.38%p32
2026-10-24
CVE-2024-41918

'Rakuten Ichiba App' for Android 12.4.0 and earlier and 'Rakuten Ichiba App' for iOS 11.7.0 and earlier are vulnerable to improper authorization in handler for custom URL scheme. An arbitrary site may be displayed on the WebView of the product via Intent from another application installed on the user's device. As a result, the user may be redirected to an unauthorized site, and the user may become a victim of a phishing attack.

MEDIUM6.1
0.32%p25
2026-06-17
CVE-2026-53418

Improper Authorization in Handler for Custom URL Scheme in Zoom Workplace for Android before version 7.2.1 may allow an unauthenticated user to conduct an escalation of privilege via network access.

HIGH8.1
0.30%p23
2026-10-14
CVE-2026-113411

A vulnerability was found in Nerimity Desktop up to 2.2.2. Affected by this issue is the function shell.openExternal of the file src/mainWindow.js of the component Window Open Handler. The manipulation of the argument url results in improper authorization in handler for custom url scheme. The attack can be executed remotely. The exploit has been made public and could be used. Upgrading to version 2.3.3 can resolve this issue. The patch is identified as f4df21bbc290f6c1956d899cf4da9e963074a6e4. You should upgrade the affected component. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.

MEDIUM6.3
0.29%p21
2026-10-22
CVE-2024-45203

Improper authorization in handler for custom URL scheme issue in "@cosme" App for Android versions prior 5.69.0 and "@cosme" App for iOS versions prior to 6.74.0 allows an attacker to lead a user to access an arbitrary website via the vulnerable App. As a result, the user may become a victim of a phishing attack.

MEDIUM4.3
0.29%p22
2026-06-17
CVE-2024-35298

Improper authorization in handler for custom URL scheme issue in 'ZOZOTOWN' App for Android versions prior to 7.39.6 allows an attacker to lead a user to access an arbitrary website via another application installed on the user's device. As a result, the user may become a victim of a phishing attack.

MEDIUM4.3
0.29%p21
2026-06-17
CVE-2026-6445

A flaw exists in FlashArray Purity where insufficient filtering of certain data paths could expose sensitive information to an authenticated user with low privileges.

NONE
0.28%p20
2026-07-23
CVE-2025-41408

Improper authorization in handler for custom URL scheme issue in "Yahoo! Shopping" App for Android versions prior to 14.15.0 allows a remote unauthenticated attacker may lead a user to access an arbitrary website on the vulnerable App. As a result, the user may become a victim of a phishing attack.

NONE
0.28%p20
2026-06-17
CVE-2026-33335

Vikunja is an open-source self-hosted task management platform. Starting in version 0.21.0 and prior to version 2.2.0, the Vikunja Desktop Electron wrapper passes URLs from `window.open()` calls directly to `shell.openExternal()` without any validation or protocol allowlisting. An attacker who can place a link with `target="_blank"` (or that otherwise triggers `window.open`) in user-generated content can cause the victim's operating system to open arbitrary URI schemes, invoking local applications, opening local files, or triggering custom protocol handlers. Version 2.2.0 patches the issue.

HIGH8.0
0.26%p17
2026-06-17
CVE-2026-1046

Mattermost Desktop App versions <=6.0 6.2.0 5.2.13.0 fail to validate help links which allows a malicious Mattermost server to execute arbitrary executables on a user’s system via the user clicking on certain items in the Help menu Mattermost Advisory ID: MMSA-2026-00577

MEDIUM6.5
0.26%p17
2026-10-15
CVE-2025-5020

Opening maliciously-crafted URLs in Firefox from other apps such as Safari could have allowed attackers to spoof website addresses if the URLs utilized non-HTTP schemes used internally by the Firefox iOS client. This vulnerability was fixed in Firefox for iOS 139.

MEDIUM4.3
0.24%p14
2026-10-05
CVE-2026-53407

Improper Authorization in Handler for Custom URL Scheme in Zoom Workplace before version 7.0.4 for Android and before 7.0.3 for iOS may allow an unauthenticated user to conduct an escalation of privilege via network access.

CRITICAL9.8
0.23%p14
2026-10-25
CVE-2026-53408

Improper Authorization in Handler for Custom URL Scheme in Zoom Workplace before version 7.0.4 for Android and before 7.0.3 for iOS may allow an unauthenticated user to conduct an escalation of privilege via network access.

HIGH8.1
0.21%p11
2026-10-26
CVE-2024-54014

Improper authorization in handler for custom URL scheme issue in 'Skylark' App for Android 6.2.13 and earlier and 'Skylark' App for iOS 6.2.13 and earlier allows an attacker to lead the application to access an arbitrary web site via another application installed on the user's device.

NONE
0.21%p10
2026-06-17
CVE-2026-96614

"ゲオアプリ" provided by GEO CORPORATION is vulnerable to improper authorization in handler for a custom URL scheme. An attacker may be able to cause the application's in-app browser to access an arbitrary website, potentially leading to phishing attacks or disclosure of a service's session ID.

NONE
0.19%p9
2026-10-15
CVE-2026-3471

Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent an invalid URL from loading in a pop-up window in the Mattermost Desktop App which allows a malicious server owner to repeated crash the application via calling {{window.open('javascript:alert()');}}. Mattermost Advisory ID: MMSA-2026-00618

MEDIUM6.5
0.18%p8
2026-06-17
CVE-2025-67739

In JetBrains TeamCity before 2025.11.2 improper repository URL validation could lead to local paths disclosure

LOW3.1
0.17%p6
2026-10-07
CVE-2024-54125

Improper authorization in handler for custom URL scheme issue in "Shonen Jump+" App for Android versions prior to 4.0.0 allows an attacker to lead a user to access an arbitrary website via the vulnerable App. As a result, the user may become a victim of a phishing attack.

NONE
0.17%p6
2026-06-17
CVE-2026-73335

Android application "Myna Point" is vulnerable to Improper Authorization in Handler for Custom URL Scheme (CWE-939). A malicious application installed on the user's Android device may exploit the affected application's functionality through an Intent, potentially allowing arbitrary JavaScript to be executed within the affected application.

NONE
0.14%p4
2026-08-28
CVE-2026-21062

Authorization bypass in SemClipboardService prior to SMR Aug-2026 Release 1 allows local attackers to access clipboard data.

LOW3.3
0.13%p2
2026-10-23
CVE-2026-92862

The Android application "Ticket Ryutsu Center" improperly handles custom URL schemes, allowing a malicious application to cause access to an arbitrary website via a crafted Intent.

NONE
0.11%p1
2026-10-08
CVE-2026-12190

A vulnerability has been found in Genspark AI Workspace App 2.8.4 on Android. This vulnerability affects unknown code of the component ai.mainfunc.genspark. The manipulation leads to improper authorization in handler for custom url scheme. The attack can only be performed from a local environment. The vendor was contacted early about this disclosure but did not respond in any way.

MEDIUM5.3
0.11%p1
2026-07-24
CVE-2026-12189

A flaw has been found in Moovit Bus & Public Transit App 1.18 on Android. This affects an unknown part of the component com.tranzmate. Executing a manipulation can lead to improper authorization in handler for custom url scheme. The attack can only be executed locally. The exploit has been published and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

MEDIUM5.3
0.11%p1
2026-07-24
CVE-2026-12065

A vulnerability was identified in Groww Stock, Mutual Fund, Gold App up to 20260805 on Android. This affects an unknown part of the component WebView URL Handler. The manipulation leads to improper authorization in handler for custom url scheme. It is possible to launch the attack on the physical device. The complexity of an attack is rather high. It is indicated that the exploitability is difficult. The exploit is publicly available and might be used. The vendor was contacted early about this disclosure.

LOW1.8
0.11%p1
2026-10-26