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XSS vector in the Markdown processor #1845

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s-ludwig opened this Issue Jul 16, 2017 · 1 comment

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s-ludwig commented Jul 16, 2017

It's possible to inject javascript: URLs in link targets to execute arbitrary client side scripts. All parsed URLs should be restricted to a white listed set of URI schemas to avoid this.

https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet#Image_XSS_using_the_JavaScript_directive

@s-ludwig s-ludwig added the security label Jul 16, 2017

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s-ludwig Jul 16, 2017

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Note that there is already MarkdownSettings.urlFilter that can be used by application code to avoid this, but this still needs to be safe by default.

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s-ludwig commented Jul 16, 2017

Note that there is already MarkdownSettings.urlFilter that can be used by application code to avoid this, but this still needs to be safe by default.

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