{"id":"CVE-2021-3733","details":"There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the server to the client. The greatest threat that this flaw poses is to application availability.","aliases":["BIT-libpython-2021-3733","BIT-python-2021-3733","BIT-python-min-2021-3733","PSF-2022-6"],"modified":"2026-02-23T01:50:22.468739Z","published":"2022-03-10T17:42:59.623Z","related":["ALSA-2021:4160","ALSA-2022:1764","ALSA-2022:1821","MGASA-2021-0435","MGASA-2021-0457","SUSE-SU-2021:3477-1","SUSE-SU-2021:3486-1","SUSE-SU-2021:3489-1","SUSE-SU-2021:3524-1","SUSE-SU-2021:4015-1","SUSE-SU-2021:4015-2","SUSE-SU-2021:4104-1","SUSE-SU-2022:1485-1","openSUSE-SU-2021:1418-1","openSUSE-SU-2021:3489-1","openSUSE-SU-2021:4104-1","openSUSE-SU-2024:11202-1","openSUSE-SU-2024:11284-1","openSUSE-SU-2024:11286-1"],"references":[{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2024/12/msg00000.html"},{"type":"ADVISORY","url":"https://bugs.python.org/issue43075"},{"type":"ADVISORY","url":"https://bugzilla.redhat.com/show_bug.cgi?id=1995234"},{"type":"ADVISORY","url":"https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb"},{"type":"ADVISORY","url":"https://github.com/python/cpython/pull/24391"},{"type":"ADVISORY","url":"https://security.netapp.com/advisory/ntap-20220407-0001/"},{"type":"ADVISORY","url":"https://ubuntu.com/security/CVE-2021-3733"},{"type":"REPORT","url":"https://bugs.python.org/issue43075"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=1995234"},{"type":"FIX","url":"https://bugs.python.org/issue43075"},{"type":"FIX","url":"https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb"},{"type":"FIX","url":"https://github.com/python/cpython/pull/24391"},{"type":"FIX","url":"https://ubuntu.com/security/CVE-2021-3733"},{"type":"EVIDENCE","url":"https://bugs.python.org/issue43075"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/aio-libs/aiohttp","events":[{"introduced":"45b2c2c5773f0ee0d35fce8ff5716c78e91d9135"},{"fixed":"b844d4293a5bd4921bd7267550294122e83617a8"}]}],"versions":["v3.1.3","v3.9.0","v3.9.1","v3.9.2","v3.9.3","v3.9.4"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2021-3733.json"}},{"ranges":[{"type":"GIT","repo":"https://github.com/python/cpython","events":[{"introduced":"0"},{"fixed":"7215d1ae25525c92b026166f9d5cac85fb"}]}],"versions":["2.5","3.2","v0.9.8","v0.9.9","v1.0.1","v1.0.2","v1.1","v1.1.1","v1.2","v1.2b1","v1.2b2","v1.2b3","v1.2b4","v1.3","v1.3b1","v1.4","v1.4b1","v1.4b2","v1.4b3","v1.5","v1.5.1","v1.5.2","v1.5.2a1","v1.5.2a2","v1.5.2b1","v1.5.2b2","v1.5.2c1","v1.5a1","v1.5a2","v1.5a3","v1.5a4","v1.5b1","v1.5b2","v1.6a1","v1.6a2","v2.0","v2.0b1","v2.0b2","v2.0c1","v2.1","v2.1a1","v2.1a2","v2.1b1","v2.1b2","v2.1c1","v2.1c2","v2.2a3","v2.3c1","v2.3c2","v2.4","v2.4a1","v2.4a2","v2.4a3","v2.4b1","v2.4b2","v2.4c1","v2.5","v2.5.1","v2.5.1c1","v2.5.2","v2.5.2c1","v2.5.3","v2.5.3c1","v2.5.4","v2.5.5","v2.5.5c1","v2.5.5c2","v2.5.6","v2.5.6c1","v2.5a0","v2.5a1","v2.5a2","v2.5b1","v2.5b2","v2.5b3","v2.5c1","v2.5c2","v2.6","v2.6.1","v2.6.2","v2.6.2c1","v2.6.3","v2.6.3rc1","v2.6.4","v2.6.4rc1","v2.6.4rc2","v2.6.5","v2.6.5rc1","v2.6.5rc2","v2.6.6","v2.6.6rc1","v2.6.6rc2","v2.6.7","v2.6.8","v2.6.8rc1","v2.6.8rc2","v2.6a1","v2.6a2","v2.6a3","v2.6b1","v2.6b2","v2.6b3","v2.6rc1","v2.6rc2","v2.7","v2.7.1","v2.7.1rc1","v2.7.2","v2.7.2rc1","v2.7.3","v2.7.3rc1","v2.7.3rc2","v2.7.4rc1","v2.7a1","v2.7a2","v2.7a3","v2.7a4","v2.7b1","v2.7b2","v2.7rc1","v2.7rc2","v3.0a1","v3.0a2","v3.0a3","v3.0a4","v3.0a5","v3.0b1","v3.0b2","v3.0b3","v3.0rc1","v3.0rc2","v3.0rc3","v3.1","v3.1.1","v3.1.1rc1","v3.1.2","v3.1.2rc1","v3.1.3","v3.1.3rc1","v3.1.4","v3.1.4rc1","v3.1.5","v3.1.5rc1","v3.1.5rc2","v3.10.0a1","v3.10.0a2","v3.10.0a3","v3.10.0a4","v3.10.0a5","v3.10.0a6","v3.10.0a7","v3.1a1","v3.1a2","v3.1b1","v3.1rc1","v3.1rc2","v3.2","v3.2.1","v3.2.1b1","v3.2.1rc1","v3.2.1rc2","v3.2.2","v3.2.2rc1","v3.2.3","v3.2.3rc1","v3.2.3rc2","v3.2.4","v3.2.4rc1","v3.2.5","v3.2.6","v3.2.6rc1","v3.2a1","v3.2a2","v3.2a3","v3.2a4","v3.2b1","v3.2b2","v3.2rc1","v3.2rc2","v3.2rc3","v3.3.0","v3.3.0a1","v3.3.0a2","v3.3.0a3","v3.3.0a4","v3.3.0b1","v3.3.0b2","v3.3.0rc1","v3.3.0rc2","v3.3.0rc3","v3.3.1","v3.3.1rc1","v3.3.2","v3.3.3","v3.3.3rc1","v3.3.3rc2","v3.3.4","v3.3.4rc1","v3.3.5","v3.3.5rc1","v3.3.5rc2","v3.3.6","v3.3.6rc1","v3.4.0","v3.4.0a1","v3.4.0a2","v3.4.0a3","v3.4.0a4","v3.4.0b1","v3.4.0b2","v3.4.0b3","v3.4.0rc1","v3.4.0rc2","v3.4.0rc3","v3.4.1","v3.4.1rc1","v3.4.2","v3.4.2rc1","v3.4.3","v3.4.3rc1","v3.4.4","v3.4.4rc1","v3.4.5","v3.4.5rc1","v3.4.6","v3.4.6rc1","v3.5.0","v3.5.0a1","v3.5.0a2","v3.5.0a3","v3.5.0a4","v3.5.0b1","v3.5.0b2","v3.5.0b3","v3.5.0b4","v3.5.0rc1","v3.5.0rc2","v3.5.0rc3","v3.5.0rc4","v3.5.1","v3.5.1rc1","v3.5.2","v3.5.2rc1","v3.5.3","v3.5.3rc1","v3.6.0","v3.6.0a1","v3.6.0a2","v3.6.0a3","v3.6.0a4","v3.6.0b1","v3.6.0b2","v3.6.0b3","v3.6.0b4","v3.6.0rc1","v3.6.0rc2","v3.7.0a1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