Using default SSLContext for HTTPS requests in an HTTPS proxy doesn't verify certificate hostname for proxy connectionGHSA-5phf-pp7p-vc2r
MEDIUMFix: urllib3/urllib3@8d65ea1GHSA-5phf-pp7p-vc2r is a medium-severity (CVSS 6.5) CWE-295 vulnerability in urllib3. A fix is available for urllib3 — see the affected versions and patch details below.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-5phf-pp7p-vc2r by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
urllib3Real-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
Users who are using an HTTPS proxy to issue HTTPS requests and haven't configured their own SSLContext via proxy_config.
Only the default SSLContext is impacted.
Patches
urllib3 >=1.26.4 has the issue resolved. urllib3<1.26 is not impacted due to not supporting HTTPS requests via HTTPS proxies.
Workarounds
Upgrading is recommended as this is a minor release and not likely to break current usage.
Configuring an SSLContext with check_hostname=True and passing via proxy_config instead of relying on the default SSLContext
For more information
If you have any questions or comments about this advisory:
- Email us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | urllib3 | ≥ 1.26.0&&< 1.26.4 | 1.26.4pip install --upgrade 'urllib3==1.26.4' |
Affected Products
fedorafedoraprojectpeoplesoft enterprise peopletoolsoracleurllib3pythonDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for urllib3, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update urllib3 to 1.26.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5phf-pp7p-vc2r 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.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
* Red Hat OpenShift Container Platform (OCP) 4 delivers the python-urllib3 package which includes a vulnerable version of urllib3 module, however from OCP 4.6 the python-urllib3 package is no longer shipped. OCP 4.5 is out of support scope for Moderate and Low impact vulnerabilities, hence is marked Out Of Support…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenShift Container Platform 3.11 | python-urllib3-1:1.24.3-2.el7 | RHBA-2021:1147 |
Frequently Asked Questions
Is GHSA-5phf-pp7p-vc2r in your dependencies?
Find it across PyPI, including transitive dependencies.