Simon Willison’s Weblog

Removing XSLT for a more secure browser (via) Previously discussed back in August, it looks like it's now official:

Chrome intends to deprecate and remove XSLT from the browser. [...] We intend to remove support from version 155 (November 17, 2026). The Firefox and WebKit projects have also indicated plans to remove XSLT from their browser engines. [...]

The continued inclusion of XSLT 1.0 in web browsers presents a significant and unnecessary security risk. The underlying libraries that process these transformations, such as libxslt (used by Chromium browsers), are complex, aging C/C++ codebases. This type of code is notoriously susceptible to memory safety vulnerabilities like buffer overflows, which can lead to arbitrary code execution.

I mostly encounter XSLT on people's Atom/RSS feeds, converting those to a more readable format in case someone should navigate directly to that link. Jake Archibald shared an alternative solution to that back in September.