GHSA-qjxf-f2mg-c6mc is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in tornado. A fix is available for tornado — see the affected versions and patch details below.
Tornado is vulnerable to DoS due to too many multipart parts
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-qjxf-f2mg-c6mc.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-qjxf-f2mg-c6mc plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 376,715 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
tornadoReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
In versions of Tornado prior to 6.5.5, the only limit on the number of parts in multipart/form-data is the max_body_size setting (default 100MB). Since parsing occurs synchronously on the main thread, this creates the possibility of denial-of-service due to the cost of parsing very large multipart bodies with many parts.
Tornado 6.5.5 introduces new limits on the size and complexity of multipart bodies, including a default limit of 100 parts per request. These limits are configurable if needed; see tornado.httputil.ParseMultipartConfig. It is also now possible to disable multipart/form-data parsing entirely if it is not required for the application.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | tornado | all versions | 6.5.5pip install --upgrade 'tornado==6.5.5' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tornado, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update tornado to 6.5.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qjxf-f2mg-c6mc is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-qjxf-f2mg-c6mc can be triaged on real exposure rather than presence alone.
Tailored to GHSA-qjxf-f2mg-c6mc. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 10 | python-tornado-0:6.5.5-1.el10_1.1 | RHSA-2026:13641 |
| Red Hat Enterprise Linux 10 | python-tornado-0:6.5.5-1.el10_2 | RHSA-2026:19034 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | python-tornado-0:6.4.2-1.el10_0.2 | RHSA-2026:20577 |
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | python-tornado-0:4.2.1-5.el7_9.3 | RHSA-2026:24342 |
| Red Hat Enterprise Linux 8 | pcs-0:0.10.18-2.el8_10.9 | RHSA-2026:8093 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | pcs-0:0.10.8-1.el8_4.11 | RHSA-2026:11493 |
| Red Hat Enterprise Linux 8.6 Telecommunications Update Service | pcs-0:0.10.12-6.el8_6.13 | RHSA-2026:11494 |
| Red Hat Enterprise Linux 8.8 Telecommunications Update Service | pcs-0:0.10.15-4.el8_8.11 | RHSA-2026:11495 |
Frequently Asked Questions
Is GHSA-qjxf-f2mg-c6mc in your dependencies?
O3 Security finds GHSA-qjxf-f2mg-c6mc across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.