CVE-2026-31958:
Tornado is a Python web framework and asynchronous networking library. In versions of Tornado prior to 6.5.5, the only limit on the number of parts in multipart/form-data is the max_body_size setting (default 100MB). Since parsing occurs synchronously on the main thread, this creates the possibility of denial-of-service due to the cost of parsing very large multipart bodies with many parts. This vulnerability is fixed in 6.5.5.
CVE-2026-35536:
In Tornado before 6.5.5, cookie attribute injection could occur because the domain, path, and samesite arguments to .RequestHandler.set_cookie were not checked for crafted characters.
CVE-2026-31958:
Tornado is a Python web framework and asynchronous networking library. In versions of Tornado prior to 6.5.5, the only limit on the number of parts in multipart/form-data is the max_body_size setting (default 100MB). Since parsing occurs synchronously on the main thread, this creates the possibility of denial-of-service due to the cost of parsing very large multipart bodies with many parts. This vulnerability is fixed in 6.5.5.
CVE-2026-35536:
In Tornado before 6.5.5, cookie attribute injection could occur because the domain, path, and samesite arguments to .RequestHandler.set_cookie were not checked for crafted characters.
debian/patches: 1 patch with invalid metadata, 1 patch to forward upstream
high
Among the 8 debian patches
available in version 6.5.5-1 of the package,
we noticed the following issues:
1 patch with
invalid metadata that ought to be fixed.
1 patch
where the metadata indicates that the patch has not yet been forwarded
upstream. You should either forward the patch upstream or update the
metadata to document its real status.
![[bug history graph]](https://qa.debian.org/data/bts/graphs/p/python-tornado.png){kind=link}