Summary

There is a potential cross-site scripting (XSS) vulnerability that can be exploited via maliciously crafted user data.

Our filter to detect and prevent the use of the javascript: URL scheme in the href attribute of an <a> tag could be bypassed with tab \t or newline \n characters between the characters of the protocol, e.g. java\tscript:.

Impact

If you render an <a> tag with an href attribute set to a user-provided link, that link could potentially execute JavaScript when clicked by another user.

a(href: user_profile) { "Profile" }

Mitigation

The best way to mitigate this vulnerability is to update to one of the following versions:

• 1.10.1
• 1.9.2
• 1.8.3
• 1.7.2
• 1.6.3
• 1.5.3
• 1.4.2

Workarounds

Configuring a Content Security Policy that does not allow unsafe-inline would effectively prevent this vulnerability from being exploited.

References

• GHSA-g7xq-xv8c-h98c
• phlex-ruby/phlex@9e3f5b9
• https://nvd.nist.gov/vuln/detail/CVE-2024-32463
• https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy
• https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy#unsafe-inline
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/phlex/CVE-2024-32463.yml