CVE-2026-103261

medium

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.

References

https://www.vulncheck.com/advisories/tornado-before-6.5.9-denial-of-service-via-query-string

https://github.com/tornadoweb/tornado/security/advisories/GHSA-3hv7-mjh2-fv65

https://github.com/tornadoweb/tornado/commit/03945136ea9746eccf61caf88edae39642e59c93

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-90655

Details

Source: Mitre, NVD

Published: 2026-10-01

Updated: 2026-10-01

Risk Information

CVSS v2

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P

Severity: Medium

CVSS v3

Base Score: 5.3

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Severity: Medium

CVSS v4

Base Score: 6.9

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

Severity: Medium

EPSS

EPSS: 0.00467