CVE-2023-54397 Tornado before 6.3.3 HTTP Request Smuggling via Content-Length
Attackers can smuggle HTTP requests via malformed Content-Length headers in Tornado, bypassing proxy validation when deployed behind specific proxies.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-54397?
CVE-2023-54397 is a critical vulnerability in tornadoweb tornado, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Tornado before 6.3.3 contains an HTTP request smuggling vulnerability due to improper parsing of Content-Length headers accepting non-standard characters. Attackers can send crafted HTTP requests with these characters to bypass proxy validation and smuggle requests when deployed behind certain proxies.
Weakness: CWE-444
Which versions are affected by CVE-2023-54397?
2 open source packages ship an affected version, including tornado.
| Package | Affected | Fixed in |
|---|---|---|
tornado PyPI | All versions | 6.3.3 |
tornado PyPI | All versions | 6.3.3 |
How do I fix CVE-2023-54397?
Upgrade tornado to 6.3.3 or later.
Is CVE-2023-54397 being exploited?
There is no known exploitation of CVE-2023-54397 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2023-54397, GHSA-qppv-j76h-2rpx, GHSA-rhr2-ccgv-xvgx, ROOT-APP-PYPI-GHSA-qppv-j76h-2rpx, UBUNTU-CVE-2023-54397.