CVE-2020-8492

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.

CVSS 3.1

6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS

6.6% chance of exploitation in the next 30 days; higher than 93% of CVEs (scores of 2026-10-25)

CWE

CWE-400

Published

2020-01-30

Modified

2026-10-14

Record from

the NVD, synced 2026-10-19

Affected

• canonical:ubuntu_linux
• debian:debian_linux
• fedoraproject:fedora
• opensuse:leap
• python:python

References

• http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00003.html
• https://bugs.python.org/issue39503
• https://github.com/python/cpython/pull/18284
• 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

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