CWE-601
AllowedURL Redirection to Untrusted Site ('Open Redirect')
Abstraction: Base · Status: Draft
The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.
2305 vulnerabilities reference this CWE, most recent first.
GHSA-6R4C-542P-QG6C
Vulnerability from github – Published: 2022-05-17 02:24 – Updated: 2022-05-17 02:24IBM Rhapsody DM 5.0 and 6.0 could allow a remote attacker to conduct phishing attacks, using an open redirect attack. By persuading a victim to visit a specially-crafted Web site, a remote attacker could exploit this vulnerability to spoof the URL displayed to redirect a user to a malicious Web site that would appear to be trusted. This could allow the attacker to obtain highly sensitive information or conduct further attacks against the victim.
{
"affected": [],
"aliases": [
"CVE-2017-1287"
],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2017-07-24T21:29:00Z",
"severity": "MODERATE"
},
"details": "IBM Rhapsody DM 5.0 and 6.0 could allow a remote attacker to conduct phishing attacks, using an open redirect attack. By persuading a victim to visit a specially-crafted Web site, a remote attacker could exploit this vulnerability to spoof the URL displayed to redirect a user to a malicious Web site that would appear to be trusted. This could allow the attacker to obtain highly sensitive information or conduct further attacks against the victim.",
"id": "GHSA-6r4c-542p-qg6c",
"modified": "2022-05-17T02:24:08Z",
"published": "2022-05-17T02:24:08Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2017-1287"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/125148"
},
{
"type": "WEB",
"url": "http://www.ibm.com/support/docview.wss?uid=swg22006052"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-6R97-7R45-G4P2
Vulnerability from github – Published: 2025-04-08 09:31 – Updated: 2025-04-08 09:31The Advanced Advertising System plugin for WordPress is vulnerable to Open Redirect in all versions up to, and including, 1.3.1. This is due to insufficient validation on the redirect url supplied via the 'redir' parameter. This makes it possible for unauthenticated attackers to redirect users to potentially malicious sites if they can successfully trick them into performing an action.
{
"affected": [],
"aliases": [
"CVE-2025-3433"
],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-04-08T09:15:28Z",
"severity": "MODERATE"
},
"details": "The Advanced Advertising System plugin for WordPress is vulnerable to Open Redirect in all versions up to, and including, 1.3.1. This is due to insufficient validation on the redirect url supplied via the \u0027redir\u0027 parameter. This makes it possible for unauthenticated attackers to redirect users to potentially malicious sites if they can successfully trick them into performing an action.",
"id": "GHSA-6r97-7r45-g4p2",
"modified": "2025-04-08T09:31:12Z",
"published": "2025-04-08T09:31:12Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-3433"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/browser/advanced-advertising-system/trunk/shortcode.php#L165"
},
{
"type": "WEB",
"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/72a56589-9dc0-47a7-bb68-e31f84a639ee?source=cve"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-6RMF-CV6P-4H27
Vulnerability from github – Published: 2022-12-17 15:30 – Updated: 2022-12-22 19:53A vulnerability has been found in cyface Terms and Conditions Module up to 2.0.10 and classified as problematic. Affected by this vulnerability is the function returnTo of the file termsandconditions/views.py. The manipulation leads to open redirect. The attack can be launched remotely. Upgrading to version 2.0.11 can address this issue. The name of the patch is 03396a1c2e0af95e12a45c5faef7e47a4b513e1a. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-216175.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "django-termsandconditions"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.0.11"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2022-4589"
],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": true,
"github_reviewed_at": "2022-12-19T18:14:46Z",
"nvd_published_at": "2022-12-17T13:15:00Z",
"severity": "MODERATE"
},
"details": "A vulnerability has been found in cyface Terms and Conditions Module up to 2.0.10 and classified as problematic. Affected by this vulnerability is the function returnTo of the file termsandconditions/views.py. The manipulation leads to open redirect. The attack can be launched remotely. Upgrading to version 2.0.11 can address this issue. The name of the patch is 03396a1c2e0af95e12a45c5faef7e47a4b513e1a. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-216175.",
"id": "GHSA-6rmf-cv6p-4h27",
"modified": "2022-12-22T19:53:24Z",
"published": "2022-12-17T15:30:23Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-4589"
},
{
"type": "WEB",
"url": "https://github.com/cyface/django-termsandconditions/pull/239"
},
{
"type": "WEB",
"url": "https://github.com/cyface/django-termsandconditions/commit/03396a1c2e0af95e12a45c5faef7e47a4b513e1a"
},
{
"type": "PACKAGE",
"url": "https://github.com/cyface/django-termsandconditions"
},
{
"type": "WEB",
"url": "https://github.com/cyface/django-termsandconditions/releases/tag/v2.0.10"
},
{
"type": "WEB",
"url": "https://github.com/cyface/django-termsandconditions/releases/tag/v2.0.11"
},
{
"type": "WEB",
"url": "https://vuldb.com/?id.216175"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
],
"summary": "Terms and Conditions Module vulnerable to Open Redirect"
}
GHSA-6RX2-WJR5-47V3
Vulnerability from github – Published: 2025-08-19 21:30 – Updated: 2025-08-20 18:30Malicious pages could use Firefox for iOS to pass FIDO: links to the OS and trigger the hybrid passkey transport. An attacker within Bluetooth range could have used this to trick the user into using their passkey to log the attacker's computer into the target account. This vulnerability affects Firefox for iOS < 142 and Focus for iOS < 142.
{
"affected": [],
"aliases": [
"CVE-2025-55031"
],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-08-19T21:15:28Z",
"severity": "CRITICAL"
},
"details": "Malicious pages could use Firefox for iOS to pass FIDO: links to the OS and trigger the hybrid passkey transport. An attacker within Bluetooth range could have used this to trick the user into using their passkey to log the attacker\u0027s computer into the target account. This vulnerability affects Firefox for iOS \u003c 142 and Focus for iOS \u003c 142.",
"id": "GHSA-6rx2-wjr5-47v3",
"modified": "2025-08-20T18:30:20Z",
"published": "2025-08-19T21:30:37Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-55031"
},
{
"type": "WEB",
"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1979499"
},
{
"type": "WEB",
"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1979804"
},
{
"type": "WEB",
"url": "https://www.mozilla.org/security/advisories/mfsa2025-68"
},
{
"type": "WEB",
"url": "https://www.mozilla.org/security/advisories/mfsa2025-69"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-6V49-CM4J-5RG6
Vulnerability from github – Published: 2022-05-13 01:32 – Updated: 2022-05-13 01:32IBM Platform Symphony 7.1 Fix Pack 1 and 7.1.1 and IBM Spectrum Symphony 7.1.2 and 7.2.0.2 could allow a remote attacker to conduct phishing attacks, using an open redirect attack. By persuading a victim to visit a specially-crafted Web site, a remote attacker could exploit this vulnerability to spoof the URL displayed to redirect a user to a malicious Web site that would appear to be trusted. This could allow the attacker to obtain highly sensitive information or conduct further attacks against the victim. IBM X-Force ID: 146339.
{
"affected": [],
"aliases": [
"CVE-2018-1704"
],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2018-09-28T13:29:00Z",
"severity": "MODERATE"
},
"details": "IBM Platform Symphony 7.1 Fix Pack 1 and 7.1.1 and IBM Spectrum Symphony 7.1.2 and 7.2.0.2 could allow a remote attacker to conduct phishing attacks, using an open redirect attack. By persuading a victim to visit a specially-crafted Web site, a remote attacker could exploit this vulnerability to spoof the URL displayed to redirect a user to a malicious Web site that would appear to be trusted. This could allow the attacker to obtain highly sensitive information or conduct further attacks against the victim. IBM X-Force ID: 146339.",
"id": "GHSA-6v49-cm4j-5rg6",
"modified": "2022-05-13T01:32:56Z",
"published": "2022-05-13T01:32:56Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-1704"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/146339"
},
{
"type": "WEB",
"url": "https://www.ibm.com/support/docview.wss?uid=ibm10719671"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-6VPC-JMR8-RH6F
Vulnerability from github – Published: 2025-02-12 00:32 – Updated: 2025-02-14 21:31Dedecms 5.71sp1 and earlier is vulnerable to URL redirect. In the web application, a logic error does not judge the input GET request resulting in URL redirection.
{
"affected": [],
"aliases": [
"CVE-2024-57241"
],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-02-11T22:15:29Z",
"severity": "MODERATE"
},
"details": "Dedecms 5.71sp1 and earlier is vulnerable to URL redirect. In the web application, a logic error does not judge the input GET request resulting in URL redirection.",
"id": "GHSA-6vpc-jmr8-rh6f",
"modified": "2025-02-14T21:31:03Z",
"published": "2025-02-12T00:32:16Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-57241"
},
{
"type": "WEB",
"url": "https://github.com/woshidaheike/dedecms-url-redirection"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-6VX9-9R2G-8373
Vulnerability from github – Published: 2025-05-28 17:39 – Updated: 2025-05-28 20:04Summary
This advisory addresses an Open Redirection vulnerability in Mautic's user unlocking endpoint. This vulnerability could be exploited by an attacker to redirect legitimate users to malicious websites, potentially leading to phishing attacks or the delivery of exploit kits.
Open Redirection via returnUrl Parameter: An Open Redirection vulnerability exists in the /s/action/unlock/user.user/0 endpoint. The returnUrl parameter, intended for post-action redirection, is not properly validated. This allows an attacker to craft a URL that, when clicked by a user, redirects them to an arbitrary external website controlled by the attacker.
Mitigation
Update Mautic to a version that properly validates or sanitizes the returnUrl parameter to ensure that redirects only occur to trusted, internal URLs or explicitly whitelisted domains.
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "mautic/core"
},
"ranges": [
{
"events": [
{
"introduced": "1.0.0"
},
{
"fixed": "4.4.16"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "mautic/core"
},
"ranges": [
{
"events": [
{
"introduced": "5.0.0-alpha"
},
{
"fixed": "5.2.6"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "mautic/core"
},
"ranges": [
{
"events": [
{
"introduced": "6.0.0-alpha"
},
{
"fixed": "6.0.2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-5256"
],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": true,
"github_reviewed_at": "2025-05-28T17:39:45Z",
"nvd_published_at": "2025-05-28T18:15:34Z",
"severity": "MODERATE"
},
"details": "### Summary\nThis advisory addresses an Open Redirection vulnerability in Mautic\u0027s user unlocking endpoint. This vulnerability could be exploited by an attacker to redirect legitimate users to malicious websites, potentially leading to phishing attacks or the delivery of exploit kits.\n\nOpen Redirection via `returnUrl` Parameter: An Open Redirection vulnerability exists in the `/s/action/unlock/user.user/0` endpoint. The `returnUrl` parameter, intended for post-action redirection, is not properly validated. This allows an attacker to craft a URL that, when clicked by a user, redirects them to an arbitrary external website controlled by the attacker.\n\n### Mitigation\nUpdate Mautic to a version that properly validates or sanitizes the `returnUrl` parameter to ensure that redirects only occur to trusted, internal URLs or explicitly whitelisted domains.",
"id": "GHSA-6vx9-9r2g-8373",
"modified": "2025-05-28T20:04:40Z",
"published": "2025-05-28T17:39:45Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/mautic/mautic/security/advisories/GHSA-6vx9-9r2g-8373"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-5256"
},
{
"type": "PACKAGE",
"url": "https://github.com/mautic/mautic"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N",
"type": "CVSS_V3"
}
],
"summary": "Mautic has an Open Redirect vulnerability on user unlock path."
}
GHSA-6WVC-J264-82HV
Vulnerability from github – Published: 2023-07-06 19:24 – Updated: 2024-04-04 05:34Rapid7 InsightVM versions 6.6.178 and lower suffers from an open redirect vulnerability, whereby an attacker has the ability to redirect the user to a site of the attacker’s choice using the ‘page’ parameter of the ‘data/console/redirect’ component of the application. This issue was resolved in the February, 2023 release of version 6.6.179.
{
"affected": [],
"aliases": [
"CVE-2023-0681"
],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-03-20T20:15:00Z",
"severity": "MODERATE"
},
"details": "Rapid7 InsightVM versions 6.6.178 and lower suffers from an open redirect vulnerability, whereby an attacker has the ability to redirect the user to a site of the attacker\u2019s choice using the \u2018page\u2019 parameter of the \u2018data/console/redirect\u2019 component of the application. This issue was resolved in the February, 2023 release of version 6.6.179.",
"id": "GHSA-6wvc-j264-82hv",
"modified": "2024-04-04T05:34:53Z",
"published": "2023-07-06T19:24:12Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-0681"
},
{
"type": "WEB",
"url": "https://docs.rapid7.com/release-notes/nexpose/20230208"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-6WXR-G84W-3H8X
Vulnerability from github – Published: 2025-07-04 03:30 – Updated: 2025-07-04 03:30The AI Engine plugin for WordPress is vulnerable to open redirect in version 2.8.4. This is due to an insecure OAuth implementation, as the 'redirect_uri' parameter is missing validation during the authorization flow. This makes it possible for unauthenticated attackers to intercept the authorization code and obtain an access token by redirecting the user to an attacker-controlled URI. Note: OAuth is disabled, the 'Meow_MWAI_Labs_OAuth' class is not loaded in the plugin in the patched version 2.8.5.
{
"affected": [],
"aliases": [
"CVE-2025-6238"
],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-07-04T03:15:22Z",
"severity": "HIGH"
},
"details": "The AI Engine plugin for WordPress is vulnerable to open redirect in version 2.8.4. This is due to an insecure OAuth implementation, as the \u0027redirect_uri\u0027 parameter is missing validation during the authorization flow. This makes it possible for unauthenticated attackers to intercept the authorization code and obtain an access token by redirecting the user to an attacker-controlled URI. Note: OAuth is disabled, the \u0027Meow_MWAI_Labs_OAuth\u0027 class is not loaded in the plugin in the patched version 2.8.5.",
"id": "GHSA-6wxr-g84w-3h8x",
"modified": "2025-07-04T03:30:31Z",
"published": "2025-07-04T03:30:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-6238"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/browser/ai-engine/tags/2.8.4/labs/oauth.php"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/changeset/3321384/ai-engine/trunk/labs/mcp.php"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/changeset/3321384/ai-engine/trunk/labs/oauth.php"
},
{
"type": "WEB",
"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/1edc84fd-8cb5-4899-9444-1b6ae3144917?source=cve"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-6X28-CQMJ-V2H4
Vulnerability from github – Published: 2022-05-24 16:54 – Updated: 2024-04-04 01:46Search Guard Kibana Plugin versions before 5.6.8-7 and before 6.x.y-12 had an issue that an attacker can redirect the user to a potentially malicious site upon Kibana login.
{
"affected": [],
"aliases": [
"CVE-2019-13422"
],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2019-08-23T14:15:00Z",
"severity": "MODERATE"
},
"details": "Search Guard Kibana Plugin versions before 5.6.8-7 and before 6.x.y-12 had an issue that an attacker can redirect the user to a potentially malicious site upon Kibana login.",
"id": "GHSA-6x28-cqmj-v2h4",
"modified": "2024-04-04T01:46:45Z",
"published": "2022-05-24T16:54:37Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-13422"
},
{
"type": "WEB",
"url": "https://docs.search-guard.com/6.x-25/changelog-kibana-6.x-12"
},
{
"type": "WEB",
"url": "https://search-guard.com/cve-advisory"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
Mitigation MIT-5
Strategy: Input Validation
- Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
- Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- Use a list of approved URLs or domains to be used for redirection.
Mitigation
Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
Mitigation MIT-21.2
Strategy: Enforcement by Conversion
- When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
- For example, ID 1 could map to "/login.asp" and ID 2 could map to "http://www.example.com/". Features such as the ESAPI AccessReferenceMap [REF-45] provide this capability.
Mitigation
Ensure that no externally-supplied requests are honored by requiring that all redirect requests include a unique nonce generated by the application [REF-483]. Be sure that the nonce is not predictable (CWE-330).
Mitigation MIT-6
Strategy: Attack Surface Reduction
- Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
- Many open redirect problems occur because the programmer assumed that certain inputs could not be modified, such as cookies and hidden form fields.
Mitigation MIT-29
Strategy: Firewall
Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].
CAPEC-178: Cross-Site Flashing
An attacker is able to trick the victim into executing a Flash document that passes commands or calls to a Flash player browser plugin, allowing the attacker to exploit native Flash functionality in the client browser. This attack pattern occurs where an attacker can provide a crafted link to a Flash document (SWF file) which, when followed, will cause additional malicious instructions to be executed. The attacker does not need to serve or control the Flash document. The attack takes advantage of the fact that Flash files can reference external URLs. If variables that serve as URLs that the Flash application references can be controlled through parameters, then by creating a link that includes values for those parameters, an attacker can cause arbitrary content to be referenced and possibly executed by the targeted Flash application.