CVE-2026-103261
Publication date 2 October 2026
Last updated 2 October 2026
Ubuntu priority
Description
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| python-tornado | 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:
Base score
6.9 · Medium
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
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-2026-103261
- https://github.com/tornadoweb/tornado/security/advisories/GHSA-3hv7-mjh2-fv65
- https://github.com/tornadoweb/tornado/commit/03945136ea9746eccf61caf88edae39642e59c93
- https://www.vulncheck.com/advisories/tornado-before-6.5.9-denial-of-service-via-query-string