6.9

CVE-2026-103261: tornadoweb tornado

CVSS: 6.9v4.0MediumDeferred
AliasesGHSA-3hv7-mjh2-fv65UBUNTU-CVE-2026-103261DEBIAN-CVE-2026-103261
Published 01-10-2026Last modified 01-10-2026
Open JSON

Vulnerability summary

CVE-2026-103261 is a medium (CVSS 6.9) vulnerability in tornadoweb tornado. EPSS estimates a 0.47% chance of exploitation in the next 30 days, higher than 39.1% of scored vulnerabilities.

Overall risk
28/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.9/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.47%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 01-10-2026
    PublishedVulnerability first disclosed.
  2. 01-10-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

8 scores · 5 sources · 2 versions

EPSS trend

Probability

0.47%

Chance of exploitation in the next 30 days

Percentile

39%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

02-10-202620-10-2026
EPSS score
0.47%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian1 product
  • python-tornadoAll versions (No fix recorded)
PyPI1 product
  • tornado< 6.5.9
Tornadoweb1 product
Ubuntu1 product
  • python-tornadoAll versions (No fix recorded)

4 vendors · 4 products

References

10 links