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 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.

CVSS v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://github.com/tornadoweb/tornado/commit/03945136ea9746eccf61caf88edae39642e59c93
https://github.com/tornadoweb/tornado/security/advisories/GHSA-3hv7-mjh2-fv65
https://www.vulncheck.com/advisories/tornado-before-6.5.9-denial-of-service-via-query-string

Configurations

No configuration.

History

01 Oct 2026, 11:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-01 11:17

Updated : 2026-10-01 15:17

NVD link : CVE-2026-103261

Mitre link : CVE-2026-103261

CVE.ORG link : CVE-2026-103261

JSON object : View

Products Affected

No product.

CWE

CWE-770

Allocation of Resources Without Limits or Throttling

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