USN-8198-1: Tornado vulnerabilities

Publication date

22 April 2026

Overview

Several security issues were fixed in Tornado.


Packages

Details

It was discovered that Tornado incorrectly handled parsing of large
multipart request bodies. An attacker could possibly use this issue to
cause a denial of service. (CVE-2026-31958)

It was discovered that Tornado did not properly validate characters in
cookie values. An attacker could possibly use this issue to inject
arbitrary cookie attributes. (CVE-2026-35536)

It was discovered that Tornado incorrectly handled parsing of large
multipart request bodies. An attacker could possibly use this issue to
cause a denial of service. (CVE-2026-31958)

It was discovered that Tornado did not properly validate characters in
cookie values. An attacker could possibly use this issue to inject
arbitrary cookie attributes. (CVE-2026-35536)

Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
25.10 questing python3-tornado –  6.4.2-3ubuntu0.3
24.04 LTS noble python3-tornado –  6.4.0-1ubuntu0.5
22.04 LTS jammy python3-tornado –  6.1.0-3ubuntu0.1~esm5  
20.04 LTS focal python3-tornado –  6.0.3+really5.1.1-3ubuntu0.1~esm5  
18.04 LTS bionic python-tornado –  4.5.3-1ubuntu0.2+esm3  
python3-tornado –  4.5.3-1ubuntu0.2+esm3  
16.04 LTS xenial python-tornado –  4.2.1-1ubuntu3.1+esm3  
python3-tornado –  4.2.1-1ubuntu3.1+esm3  

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