Tornado: Out-of-bounds memory access in C extension
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Partial Red Hat: 14 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-126 and the CVSS impact.
Summary
Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, the optional native extension tornado.speedups implemented websocket_mask without validating that the mask argument is exactly four bytes, allowing the C function to read up to three bytes beyond the provided buffer when reached through Tornado XSRF token decoding with the native extension active. This issue is fixed in version 6.5.6.
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 6.5.6 | 6.5.6 | Patch available | CNA |
| — | tornado (PyPI) | before 6.5.6 | 6.5.6 | Patch available | GHSA-cx3h-4qpv-8hc9 |
- tornado Vendortornadoweb Affected before 6.5.6 Fixed in 6.5.6 Patch available CNA
- tornado (PyPI) Vendor— Affected before 6.5.6 Fixed in 6.5.6 Patch available GHSA-cx3h-4qpv-8hc9
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 6.5.6
- Fix · GHSA-cx3h-4qpv-8hc9 tornado (PyPI) Fixed in 6.5.6 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Exploit Intelligence | Affected | No fix yet: Fix deferred |
| External Secrets Operator for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Lightspeed Core | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Applications 8 | Affected | No fix yet: Fix deferred |
| 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 7 | Affected | No fix planned: Out of support scope |
| 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 |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-49854
- 2026-10-03 Alias added: GHSA-cx3h-4qpv-8hc9
- 2026-11-06 Affected versions changed · Red Hat
References
Other 5
- https://github.com/tornadoweb/tornado/security/advisories/GHSA-cx3h-4qpv-8hc9
- https://github.com/tornadoweb/tornado/pull/3626
- https://github.com/tornadoweb/tornado/commit/96dc88c2a05705287856b2cd6b4b4034f9a6aaac
- https://github.com/tornadoweb/tornado/releases/tag/v6.5.6
- https://github.com/tornadoweb/tornado
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-2026-49854 · CVE Program
- CVE-2026-49854 · NVD
- FIRST EPSS
- GHSA-cx3h-4qpv-8hc9 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-49854 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences