CVE-2023-47627
MEDIUMCVE-2023-47627 is a medium-severity (CVSS 5.3) CWE-444 vulnerability in aiohttp. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2023-47627 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Request smuggling in aiohttp
Blast Radius
aiohttpReal-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
aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. The HTTP parser in AIOHTTP has numerous problems with header parsing, which could lead to request smuggling. This parser is only used when AIOHTTP_NO_EXTENSIONS is enabled (or not using a prebuilt wheel). These bugs have been addressed in commit d5c12ba89 which has been included in release version 3.8.6. Users are advised to upgrade. There are no known workarounds for these issues.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | aiohttp | all versions | 3.8.6 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for aiohttp. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update aiohttp to 3.8.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-47627 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 pinpoints whether CVE-2023-47627 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2023-47627. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-47627 in your dependencies?
O3 detects CVE-2023-47627 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.