CVE-2021-28363
Description
The urllib3 library 1.26.x before 1.26.4 for Python omits SSL certificate validation in some cases involving HTTPS to HTTPS proxies. The initial connection to the HTTPS proxy (if an SSLContext isn't given via proxy_config) doesn't verify the hostname of the certificate. This means certificates for different servers that still validate properly with the default urllib3 SSLContext will be silently accepted.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Arch Fixed 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Fixed | 1.26.4-1 |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 1.26.4-1 |
| sid | Fixed | 1.26.4-1 |
| forky | Fixed | 1.26.4-1 |
| bullseye | Fixed | 1.26.4-1 |
| bookworm | Fixed | 1.26.4-1 |
References
- https://github.com/urllib3/urllib3/security/advisories/GHSA-5phf-pp7p-vc2r
- https://nvd.nist.gov/vuln/detail/CVE-2021-28363
- https://github.com/urllib3/urllib3/commit/8d65ea1ecf6e2cdc27d42124e587c1b83a3118b0
- https://github.com/pypa/advisory-database/tree/main/vulns/urllib3/PYSEC-2021-59.yaml
- https://github.com/pypa/advisory-db/tree/main/vulns/urllib3/PYSEC-2021-59.yaml
- https://github.com/urllib3/urllib3
- https://github.com/urllib3/urllib3/blob/main/CHANGES.rst#1264-2021-03-15
- https://github.com/urllib3/urllib3/commits/main
- https://github.com/urllib3/urllib3/releases/tag/1.26.4
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4S65ZQVZ2ODGB52IC7VJDBUK4M5INCXL
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4S65ZQVZ2ODGB52IC7VJDBUK4M5INCXL
- https://pypi.org/project/urllib3/1.26.4
- https://security.gentoo.org/glsa/202107-36
- https://security.gentoo.org/glsa/202305-02
- https://security.netapp.com/advisory/ntap-20240621-0007
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://pypi.org/project/urllib3/1.26.4/
- https://www.suse.com/security/cve/CVE-2021-28363.html
- https://security-tracker.debian.org/tracker/CVE-2021-28363
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.