Affected: twisted, twistedmatrix twisted

Twisted is an event-based framework for internet applications, supporting Python 3.6+. The `twisted.web.util.redirectTo` function contains an HTML injection vulnerability. If application code allows an attacker to control the redirect URL this vulnerability may result in Reflected Cross-Site Scripting (XSS) in the redirect response HTML body. This vulnerability is fixed in 24.7.0rc1.

Affected: PyPI: twisted

### Summary

The `twisted.web.util.redirectTo` function contains an HTML injection vulnerability. If application code allows an attacker to control the redirect URL this vulnerability may result in Reflected Cross-Site Scripting (XSS) in the redirect response HTML body.

### Details Twisted’s `redirectTo` function generates an `HTTP 302 Redirect` response. The response contains an HTML body, built for exceptional cases where the browser doesn’t properly handle the redirect, allowing the user to click a link, navigating them to the specified destination.

The function reflects the destination URL in the HTML body without any output encoding. ```python # https://github.com/twisted/twisted/blob/trunk/src/twisted/web/_template_util.py#L88 def redirectTo(URL: bytes, request: IRequest) -> bytes: # ---snip--- content = b""" <html> <head> <meta http-equiv=\"refresh\" content=\"0;URL=%(url)s\"> </head> <body bgcolor=\"#FFFFFF\" text=\"#000000\"> <a href=\"%(url)s\">click here</a> </body> </html> """ % { b"url": URL } return content ```

If an attacker has full or partial control over redirect location due to an application bug, also known as an “Open Redirect”, they may inject arbitrary HTML into the response’s body, ultimately leading to an XSS attack.

It’s worth noting that the issue is known to maintainers and tracked with GitHub [Issue#9839](https://github.com/twisted/twisted/issues/9839). The issue description, however, does…

Affected: PyPI: twisted

Twisted is an event-based framework for internet applications, supporting Python 3.6+. The `twisted.web.util.redirectTo` function contains an HTML injection vulnerability. If application code allows an attacker to control the redirect URL this vulnerability may result in Reflected Cross-Site Scripting (XSS) in the redirect response HTML body. This vulnerability is fixed in 24.7.0rc1.