CVE-2020-26137 CRLF injection in urllib3
Medium 6.5
Published
Updated
Check this codebase for CVE-2020-26137 and fix it if it is affected.
What it is: CVE-2020-26137 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 29 Sep 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-26137 in the wild and no public exploit code.
Affected packages and fixed versions:
- urllib3 (PyPI): affected all versions; fixed in 1.25.9
- urllib3 (PyPI): affected all versions; fixed in 1.25.9
- urllib3 (PyPI): affected all versions; fixed in 1.25.9
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2020-26137/ (Markdown: https://insights.sbomify.com/CVE-2020-26137/index.md)
Attackers can inject CRLF characters into HTTP requests via the request method, potentially leading to request smuggling or header injection.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-26137?
CVE-2020-26137 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 29 Sep 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
Weakness: CWE-74
Which versions are affected by CVE-2020-26137?
3 open source packages ship an affected version, including urllib3. It affects 5 products.
| Package | Affected | Fixed in |
|---|---|---|
urllib3 PyPI | All versions | 1.25.9 |
urllib3 PyPI | All versions | 1.25.9 |
urllib3 PyPI | All versions | 1.25.9 |
Linux distribution packages (37)
python3-urllib3 AlmaLinux:8 | All versions | 1.24.2-5.el8 |
python-urllib3 Red Hat:enterprise_linux:8::baseos | All versions | 0:1.24.2-5.el8 |
python3-urllib3 Red Hat:enterprise_linux:8::baseos | All versions | 0:1.24.2-5.el8 |
python-urllib3 Rocky Linux:8 | All versions | 0:1.24.2-5.el8 |
python-asn1crypto SUSE:Enterprise Storage 6 | All versions | 0.24.0-3.2.1 |
python-boto3 SUSE:Enterprise Storage 6 | All versions | 1.17.9-19.1 |
python-botocore SUSE:Enterprise Storage 6 | All versions | 1.20.9-33.1 |
python-pyasn1 SUSE:Enterprise Storage 6 | All versions | 0.4.2-3.2.1 |
python-pycparser SUSE:Enterprise Storage 6 | All versions | 2.17-3.2.1 |
python-urllib3 SUSE:Enterprise Storage 6 | All versions | 1.25.10-9.14.1 |
python-urllib3 SUSE:HPE Helion OpenStack 8 | All versions | 1.25.10-3.31.2 |
python-asn1crypto SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOS | All versions | 0.24.0-3.2.1 |
python-boto3 SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOS | All versions | 1.17.9-19.1 |
python-botocore SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOS | All versions | 1.20.9-33.1 |
python-pyasn1 SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOS | All versions | 0.4.2-3.2.1 |
python-pycparser SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOS | All versions | 2.17-3.2.1 |
python-urllib3 SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOS | All versions | 1.25.10-9.14.1 |
python-asn1crypto SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSS | All versions | 0.24.0-3.2.1 |
python-boto3 SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSS | All versions | 1.17.9-19.1 |
python-botocore SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSS | All versions | 1.20.9-33.1 |
python-pyasn1 SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSS | All versions | 0.4.2-3.2.1 |
python-pycparser SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSS | All versions | 2.17-3.2.1 |
python-urllib3 SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSS | All versions | 1.25.10-9.14.1 |
python-asn1crypto SUSE:Linux Enterprise Micro 5.0 | All versions | 0.24.0-3.2.1 |
python-cffi SUSE:Linux Enterprise Micro 5.0 | All versions | 1.13.2-3.2.5 |
python-cryptography SUSE:Linux Enterprise Micro 5.0 | All versions | 2.8-10.1 |
python-pyOpenSSL SUSE:Linux Enterprise Micro 5.0 | All versions | 17.5.0-8.3.1 |
python-pyasn1 SUSE:Linux Enterprise Micro 5.0 | All versions | 0.4.2-3.2.1 |
python-pycparser SUSE:Linux Enterprise Micro 5.0 | All versions | 2.17-3.2.1 |
python-urllib3 SUSE:Linux Enterprise Micro 5.0 | All versions | 1.25.10-9.14.1 |
python-urllib3 SUSE:Linux Enterprise Module for Basesystem 15 SP1 | All versions | 1.24-9.10.1 |
python-asn1crypto SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 0.24.0-3.2.1 |
python-boto3 SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 1.17.9-19.1 |
python-botocore SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 1.20.9-33.1 |
python-cffi SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 1.13.2-3.2.5 |
python-cryptography SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 2.8-10.1 |
python-pyOpenSSL SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 17.5.0-8.3.1 |
Products include Canonical Ubuntu Linux, Debian Debian Linux, Oracle Communications Cloud Native Core Network Function Cloud Native Environment, Oracle Zfs Storage Appliance Kit, Python Urllib3.
How do I fix CVE-2020-26137?
Upgrade urllib3 to 1.25.9 or later.
Is CVE-2020-26137 being exploited?
There is no known exploitation of CVE-2020-26137 in the wild and no public exploit code.
Other vulnerabilities in Canonical Ubuntu Linux
Sources
Also known as ALPINE-CVE-2020-26137, ALSA-2021:1631, CLEANSTART-2026-RX33339, CLEANSTART-2026-YH76690, DEBIAN-CVE-2020-26137, GHSA-wqvq-5m8c-6g24 and 17 more.