Tornado before 6.5.9 Denial of Service via Query String
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Partial Red Hat: 13 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-770.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| tornadoweb | tornado | before 6.5.9 | 6.5.9 | Patch available | CNA |
- tornado Vendortornadoweb Affected before 6.5.9 Fixed in 6.5.9 Patch available CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:tornadoweb:tornado:*:*:*:*:*:*:*:* | — | — | tornadoweb |
- cpe:2.3:a:tornadoweb:tornado:*:*:*:*:*:*:*:* Versions — — ·tornadoweb
Remediation
- Fix · CNA tornado (tornadoweb) Fixed in 6.5.9
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
tornadoweb tornado 6.5.9
3 records Highest priority Priority HIGH 2 HIGH, 1 LOW
Other records, highest priority first
- TI-2026-65637 Tornado before 6.5.9 Denial of Service via CurlAsyncHTTPClientPriority HIGH 77
- TI-2026-65638 Tornado before 6.5.9 StaticFileHandler Path Traversal via SymlinkPriority HIGH 69
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Lightspeed Core | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Applications 8 | Affected | No fix planned: Out of support scope |
| OpenShift Lightspeed | Affected | No fix yet: Fix deferred |
| Red Hat Ansible Automation Platform 2 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux AI (RHEL AI) 3 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
| Red Hat OpenStack Platform 16.2 | Affected | No fix planned: Out of support scope |
| Red Hat OpenStack Platform 17.1 | Affected | No fix planned: Out of support scope |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-103261
- 2026-10-03 Alias added: GHSA-2v9w-f3h6-74rj
- 2026-10-31 Affected versions changed · Red Hat
References
More tornadoweb vulnerabilities
- TI-2026-65637 Tornado before 6.5.9 Denial of Service via CurlAsyncHTTPClient CVSS 4.0HIGH 8.7
- TI-2026-62120 Tornado before 6.5.8 Memory Amplification DoS via multipart CVSS 4.0HIGH 8.7
- TI-2024-13023 Tornado before 6.4.1 HTTP Request Smuggling via Transfer-Encoding CVSS 4.0CRITICAL 9.0
- TI-2026-65638 Tornado before 6.5.9 StaticFileHandler Path Traversal via Symlink CVSS 4.0HIGH 8.2
- TI-2026-62122 Tornado before 6.5.7 Credential Leak via Handle Reuse CVSS 4.0HIGH 8.2
- TI-2026-62121 Tornado before 6.5.8 Cookie Attribute Injection via Capitalized kwargs CVSS 4.0MEDIUM 6.3
Sources
- CVE-2026-103261 · CVE Program
- CVE-2026-103261 · NVD
- FIRST EPSS
- GHSA-2v9w-f3h6-74rj · GitHub Advisory Database · CC BY 4.0
- CVE-2026-103261 · Red Hat security data · CC BY 4.0
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