What’s Vulnerable › Vulnerabilities
CVE-2021-28861
- Severity: high (CVSS 7.4 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 2.7% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2022-08-23 · updated 2026-10-14
- Weakness: CWE-601
Description
Python 3.x through 3.10 has an open redirection vulnerability in lib/http/server.py due to no protection against multiple (/) at the beginning of URI path which may leads to information disclosure. NOTE: this is disputed by a third party because the http.server.html documentation page states "Warning: http.server is not recommended for production. It only implements basic security checks."
Affected products
- Fedoraproject Fedora: 35, 36, 37
- Python: from 3.0.0 before 3.7.14; from 3.8.0 before 3.8.14; from 3.9.0 before 3.9.14; from 3.10.0 before 3.10.6; 3.11.0-alpha1, 3.11.0-alpha2, 3.11.0-alpha3, 3.11.0-alpha4, 3.11.0-alpha5, 3.11.0-alpha6 (+4) — fixed in 3.10.6, 3.7.14, 3.8.14, 3.9.14
How to fix
Upgrade to a fixed version: Python 3.10.6, 3.7.14, 3.8.14, 3.9.14. Check the vendor advisory for mitigations.
References
- https://bugs.python.org/issue43223
- https://github.com/python/cpython/pull/24848
- https://github.com/python/cpython/pull/93879
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2TRINJE3INWDVIHIABW4L2NP3RUSK7BJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5LTSPFIULY2GZJN3QYNFVM4JSU6H4D6J/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5OABQ5CMPQETJLFHROAXDIDXCMDTNVYG/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DISZAFSIQ7IAPAEQTC7G2Z5QUA2V2PSW/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HPX4XHT2FGVQYLY2STT2MRVENILNZTTU/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/I3MQT5ZE3QH5PVDJMERTBOCILHK35CBE/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IFGV7P2PYFBMK32OKHCAC2ZPJQV5AUDF/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KRGKPYA5YHIXQAMRIXO5DSCX7D4UUW4Q/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OKYE2DOI2X7WZXAWTQJZAXYIWM37HDCY/
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