CVE-2026-116577
Publication date 26 October 2026
Last updated 28 October 2026
Ubuntu priority
Description
Tornado is a Python web framework and asynchronous networking library. Prior to 6.6, Tornado's HTTP header parser accepts obsolete line folding and repeatedly concatenates short continuation lines, causing quadratic CPU consumption on the IOLoop thread. An unauthenticated client can submit a header block containing many obsolete line-folding continuations before application code runs, blocking other connections served by the process. The cost grows with max_header_size, and only availability is affected. This issue is fixed in version 6.6.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| python-tornado | 26.10 stonking |
Needs evaluation
|
| 26.04 LTS resolute |
Needs evaluation
|
|
| 24.04 LTS noble |
Needs evaluation
|
|
| 22.04 LTS jammy |
Needs evaluation
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 16.04 LTS xenial |
Needs evaluation
|
Severity score breakdown
CVSS version: CVSS v3.0
Base score
5.3 · Medium
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
References
Other references
- https://www.cve.org/CVERecord?id=CVE-2026-116577
- https://github.com/tornadoweb/tornado/security/advisories/GHSA-pcg2-g6cj-q92c
- https://github.com/tornadoweb/tornado/pull/3765
- https://github.com/tornadoweb/tornado/commit/1b7a1dc9f340f52de929852e8125aa12f25297c9
- https://github.com/tornadoweb/tornado/releases/tag/v6.6.0