Python 2.7 through 2.7.17, 3.5 through 3.5.9, 3.6 through 3.6.10, 3.7 through 3.7.6, and 3.8 through 3.8.1 allows an HTTP server to conduct Regular Expression Denial of Service (ReDoS) attacks against a client because of urllib.request.AbstractBasicAuthHandler catastrophic backtracking.
Fix
Patch, vendor advisory and mitigation references on NVD 4
- https://bugs.python.org/issue39503 Issue Tracking, Vendor Advisory
- https://github.com/python/cpython/pull/18284 Patch, Third Party Advisory
- https://bugs.python.org/issue39503 Issue Tracking, Vendor Advisory
- https://github.com/python/cpython/pull/18284 Patch, Third Party Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 6.5 · python, opensuse, canonicalNVD modified 2026-10-14 09:17
Affected (CPE criteria) 11
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:*:*:*:*cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
References 33
- http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00003.html Third Party Advisory
- https://bugs.python.org/issue39503 Issue Tracking, Vendor Advisory
- https://github.com/python/cpython/pull/18284 Patch, Third Party Advisory
- https://lists.apache.org/thread.html/rdb31a608dd6758c6093fd645aea3fbf022dd25b37109b6aaea5bc0b5%40%3Ccommits.cassandra.apache.org%3E
- https://lists.apache.org/thread.html/rfec113c733162b39633fd86a2d0f34bf42ac35f711b3ec1835c774da%40%3Ccommits.cassandra.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html Mailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7WOKDEXLYW5UQ4S7PA7E37IITOC7C56J/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A5NSAX4SC3V64PGZUPH7PRDLSON34Q5A/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/APGWEMYZIY5VHLCSZ3HD67PA5Z2UQFGH/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UESGYI5XDAHJBATEZN3MHNDUBDH47AS6/
- https://python-security.readthedocs.io/vuln/urllib-basic-auth-regex.html Exploit, Third Party Advisory
- https://security.gentoo.org/glsa/202005-09 Third Party Advisory
- https://security.netapp.com/advisory/ntap-20200221-0001/ Third Party Advisory
- https://usn.ubuntu.com/4333-1/ Third Party Advisory
- https://usn.ubuntu.com/4333-2/ Third Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00003.html Third Party Advisory
- https://bugs.python.org/issue39503 Issue Tracking, Vendor Advisory
- https://github.com/python/cpython/pull/18284 Patch, Third Party Advisory
- https://lists.apache.org/thread.html/rdb31a608dd6758c6093fd645aea3fbf022dd25b37109b6aaea5bc0b5%40%3Ccommits.cassandra.apache.org%3E
- https://lists.apache.org/thread.html/rfec113c733162b39633fd86a2d0f34bf42ac35f711b3ec1835c774da%40%3Ccommits.cassandra.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html Mailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7WOKDEXLYW5UQ4S7PA7E37IITOC7C56J/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A5NSAX4SC3V64PGZUPH7PRDLSON34Q5A/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/APGWEMYZIY5VHLCSZ3HD67PA5Z2UQFGH/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UESGYI5XDAHJBATEZN3MHNDUBDH47AS6/
- https://python-security.readthedocs.io/vuln/urllib-basic-auth-regex.html Exploit, Third Party Advisory
- https://security.gentoo.org/glsa/202005-09 Third Party Advisory
- https://security.netapp.com/advisory/ntap-20200221-0001/ Third Party Advisory
- https://usn.ubuntu.com/4333-1/ Third Party Advisory
- https://usn.ubuntu.com/4333-2/ Third Party Advisory
- https://cert-portal.siemens.com/productcert/html/ssa-398330.html