This page tracks the Ubuntu fix status. The vulnerability itself is described on the main CVE page.
View CVE-2026-103261 →
UBUNTU-CVE-2026-103261
Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop sta...
Original description
The description as published by the source.
Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.init, allowing remote attackers to cause event-loop stalling by sending requests with thousands of query parameters. Attackers can send unauthenticated GET requests with unbounded query-string field counts to degrade response times for all clients sharing the same IOLoop.
Source: OSV.dev (Open Source Vulnerabilities) OSV
Affected packages
Ubuntu:Pro:16.04:LTS
python-tornado
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:Pro:18.04:LTS
python-tornado
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:Pro:20.04:LTS
python-tornado
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:Pro:22.04:LTS
python-tornado
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:24.04:LTS
python-tornado
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:26.10
python-tornado
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:26.04:LTS
python-tornado
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
References
- report ubuntu.com
- report cve.org
- report github.com
- report github.com
- report vulncheck.com