CVE-2026-103261
Published:October 01, 2026
Updated:October 13, 2026
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.
Affected Packages
tornado (CONDA):
Affected version(s) >=6.0.1 <6.5.9Fix Suggestion:
Update to version 6.5.9https://github.com/tornadoweb/tornado.git (GITHUB):
Affected version(s) >=v6.0.0 <v6.5.9Fix Suggestion:
Update to version v6.5.9tornado (PYTHON):
Affected version(s) >=6.0 <6.5.9Fix Suggestion:
Update to version 6.5.9Additional Notes
The description of this vulnerability differs from MITRE.
Related Resources (9)
Do you need more information?
Contact UsCVSS v4
Base Score:
6.9
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Weakness Type (CWE)
Allocation of Resources Without Limits or Throttling
EPSS
Base Score:
0.47