CVE-2026-103261CWE-770denial-of-service

CVE-2026-103261

Medium · published October 1, 2026

CVSS v3.1
5.3
EPSS
0%
Percentile
39.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
6.9 · 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
EPSS
0.00467 · 39.5th percentile
Weakness
CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-10-01T15:17Z
References (3)
https://github.com/tornadoweb/tornado/commit/03945136ea9746eccf61caf88edae39642e59c93 · [email protected]https://github.com/tornadoweb/tornado/security/advisories/GHSA-3hv7-mjh2-fv65 · [email protected]https://www.vulncheck.com/advisories/tornado-before-6.5.9-denial-of-service-via-query-string · [email protected]
EPSS history
Timeline
  • 03 OCT 03:41Z
    EPSS moved — → 0%
    epss
  • 01 OCT 10:42Z
    Tornado before 6.5.9 Denial of Service via Query String
    cvelistv5