GHSA-qppv-j76h-2rpx — tornado
Fix: tornadoweb/tornado@b7a5dd2GHSA-qppv-j76h-2rpx is a CWE-444 vulnerability in tornado. A fix is available for tornado — see the affected versions and patch details below.
Tornado vulnerable to HTTP request smuggling via improper parsing of `Content-Length` fields and chunk lengths
Exploitation Status
No confirmed exploitation observed yet
- 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-qppv-j76h-2rpx.
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.
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
Summary
Tornado interprets -, +, and _ in chunk length and Content-Length values, which are not allowed by the HTTP RFCs. This can result in request smuggling when Tornado is deployed behind certain proxies that interpret those non-standard characters differently. This is known to apply to older versions of haproxy, although the current release is not affected.
Details
Tornado uses the int constructor to parse the values of Content-Length headers and chunk lengths in the following locations:
tornado/http1connection.py:445
self._expected_content_remaining = int(headers["Content-Length"])
tornado/http1connection.py:621
content_length = int(headers["Content-Length"]) # type: Optional[int]
tornado/http1connection.py:671
chunk_len = int(chunk_len_str.strip(), 16)
Because int("0_0") == int("+0") == int("-0") == int("0"), using the int constructor to parse and validate strings that should contain only ASCII digits is not a good strategy.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | tornado | all versions | 6.3.3pip install --upgrade 'tornado==6.3.3' |
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 6.3.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qppv-j76h-2rpx 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-qppv-j76h-2rpx can be triaged on real exposure rather than presence alone.
Tailored to GHSA-qppv-j76h-2rpx. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-qppv-j76h-2rpx in your dependencies?
O3 Security finds GHSA-qppv-j76h-2rpx across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.