CVE-2021-3737 Denial of service in python
A remote attacker controlling an HTTP server can cause Python client scripts to enter an infinite loop, consuming CPU resources and causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-3737?
CVE-2021-3737 is a high-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 4 Mar 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A flaw was found in python. An improperly handled HTTP response in the HTTP client code of python may allow a remote attacker, who controls the HTTP server, to make the client script enter an infinite loop, consuming CPU time. The highest threat from this vulnerability is to system availability.
Which versions are affected by CVE-2021-3737?
3 open source packages ship an affected version, including libpython, python and python-min. It affects 17 products.
| Package | Affected | Fixed in |
|---|---|---|
libpython Bitnami | From 3.6.0 | 3.6.14, 3.7.11, 3.8.11, 3.9.6 |
python Bitnami | From 3.6.0 | 3.6.14, 3.7.11, 3.8.11, 3.9.6 |
python-min Bitnami | From 3.6.0 | 3.6.14, 3.7.11, 3.8.11, 3.9.6 |
Products include Canonical Ubuntu Linux, Fedoraproject Fedora, Netapp Hci, Netapp Management Services for Element Software, Netapp Netapp Xcp Smb, Netapp Ontap Select Deploy Administration Utility and 11 more.
How do I fix CVE-2021-3737?
Upgrade libpython to a fixed version for your release line: 3.6.14, 3.7.11, 3.8.11 or 3.9.6.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-3737 being exploited?
There is no known exploitation of CVE-2021-3737 in the wild and no public exploit code.
Other vulnerabilities in Canonical Ubuntu Linux
Sources
Also known as BIT-libpython-2021-3737, BIT-python-2021-3737, BIT-python-min-2021-3737, CLSA-2022-1647958513, CLSA-2022-1647958678, CLSA-2022-1647969910 and 7 more.