CVE-2024-34064

Jinja is an extensible templating engine. The xmlattr filter in affected
versions of Jinja accepts keys containing non-attribute characters.
XML/HTML attributes cannot contain spaces, /, >, or =, as each would
then be interpreted as starting a separate attribute. If an application
accepts keys (as opposed to only values) as user input, and renders these
in pages that other users see as well, an attacker could use this to inject
other attributes and perform XSS. The fix for CVE-2024-22195 only addressed
spaces but not other characters. Accepting keys as user input is now
explicitly considered an unintended use case of the xmlattr filter, and
code that does so without otherwise validating the input should be flagged
as insecure, regardless of Jinja version. Accepting values as user input
continues to be safe. This vulnerability is fixed in 3.1.4.