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Prevent usage of unsafe target='_blank' (react/jsx-no-target-blank)

When creating a JSX element that has an a tag, it is often desired to have the link open in a new tab using the target='_blank' attribute. Using this attribute unaccompanied by rel='noreferrer', however, is a severe security vulnerability (see here for more details) This rules requires that you accompany target='_blank' attributes with rel='noreferrer'.

Rule Details

This rule aims to prevent user generated link hrefs and form actions from creating security vulnerabilities by requiring rel='noreferrer' for external link hrefs and form actions, and optionally any dynamically generated link hrefs and form actions.

Rule Options

...
"react/jsx-no-target-blank": [<enabled>, {
  "allowReferrer": <allow-referrer>,
  "enforceDynamicLinks": <enforce>,
  "links": <boolean>,
  "forms": <boolean>,
}]
...
  • allowReferrer: optional boolean. If true does not require noreferrer (i. e. noopener alone is enough, this leaves IE vulnerable). Defaults to false.
  • enabled: for enabling the rule.
  • enforceDynamicLinks: optional string, 'always' or 'never'
  • warnOnSpreadAttributes: optional boolean. Defaults to false.
  • enforceDynamicLinks - enforce: optional string, 'always' or 'never'
  • links - Prevent usage of unsafe target='_blank' inside links, defaults to true
  • forms - Prevent usage of unsafe target='_blank' inside forms, defaults to false

enforceDynamicLinks

always

{"enforceDynamicLinks": "always"} enforces the rule if the href is a dynamic link (default)

Examples of incorrect code for this rule, when configured with { "enforceDynamicLinks": "always" }:

var Hello = <a target='_blank' href="http://example.com/"></a>
var Hello = <a target='_blank' href={dynamicLink}></a>

Examples of correct code for this rule:

var Hello = <p target="_blank"></p>
var Hello = <a target="_blank" rel="noreferrer" href="http://example.com"></a>
var Hello = <a target="_blank" rel="noopener noreferrer" href="http://example.com"></a>
var Hello = <a target="_blank" href="relative/path/in/the/host"></a>
var Hello = <a target="_blank" href="/absolute/path/in/the/host"></a>
var Hello = <a></a>

never

{"enforceDynamicLinks": "never"} does not enforce the rule if the href is a dynamic link

Examples of correct code for this rule, when configured with { "enforceDynamicLinks": "never" }:

var Hello = <a target='_blank' href={dynamicLink}></a>

warnOnSpreadAttributes

Spread attributes are a handy way of passing programmatically-generated props to components, but may contain unsafe props e.g.

const unsafeProps = {
  href: "http://example.com",
  target: "_blank",
};

<a {...unsafeProps}></a>

Defaults to false. If false, this rule will ignore all spread attributes. If true, this rule will treat all spread attributes as if they contain an unsafe combination of props, unless specifically overridden by props after the last spread attribute prop e.g. the following would not be violations:

<a {...unsafeProps} rel="noreferrer"></a>
<a {...unsafeProps} target="_self"></a>
<a {...unsafeProps} href="/some-page"></a>

links / forms

When option forms is set to true, the following is considered an error:

var Hello = <form target="_blank" action="http://example.com/"></form>;

When option links is set to true, the following is considered an error:

var Hello = <a target='_blank' href="http://example.com/"></form>

Custom link components

This rule supports the ability to use custom components for links, such as <Link /> which is popular in libraries like react-router, next.js and gatsby. To enable this, define your custom link components in the global shared settings under the linkComponents configuration area. Once configured, this rule will check those components as if they were <a /> elements.

Examples of incorrect code for this rule:

var Hello = <Link target="_blank" to="http://example.com/"></Link>
var Hello = <Link target="_blank" to={dynamicLink}></Link>

Examples of correct code for this rule:

var Hello = <Link target="_blank" rel="noopener noreferrer" to="http://example.com"></Link>
var Hello = <Link target="_blank" to="relative/path/in/the/host"></Link>
var Hello = <Link target="_blank" to="/absolute/path/in/the/host"></Link>
var Hello = <Link />

Custom form components

This rule supports the ability to use custom components for forms. To enable this, define your custom form components in the global shared settings under the formComponents configuration area. Once configured, this rule will check those components as if they were <form /> elements.

When To Override It

For links to a trusted host (e.g. internal links to your own site, or links to a another host you control, where you can be certain this security vulnerability does not exist), you may want to keep the HTTP Referer header for analytics purposes.

If you do not support Internet Explorer (any version), Chrome < 49, Opera < 36, Firefox < 52, desktop Safari < 10.1 or iOS Safari < 10.3, you may set allowReferrer to true, keep the HTTP Referer header and only add rel="noopener" to your links.

When Not To Use It

If you do not have any external links or forms, you can disable this rule.