{"id":"PSF-2022-6","summary":"CVE-2021-3733: ReDoS in urllib.request","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","CVE-2021-3733"],"modified":"2026-05-18T05:47:05.768617646Z","published":"2022-03-07T00:00:00Z","database_specific":{"cwe_ids":[]},"references":[{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/cve-2021-3733"},{"type":"REPORT","url":"https://bugs.python.org/issue43075"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/python/cpython","events":[{"introduced":"0"},{"fixed":"3fbe96123aeb66664fa547a8f6022efa2dc8788f"},{"fixed":"7215d1ae25525c92b026166f9d5cac85fb1defe1"},{"fixed":"a21d4fbd549ec9685068a113660553d7f80d9b09"},{"fixed":"ada14995870abddc277addf57dd690a2af04c2da"},{"fixed":"e7654b6046090914a8323931ed759a94a5f85d60"}]}],"versions":["v3.10.0a7","v3.9.2","v3.8.8","v3.9.2rc1","v3.8.8rc1","v3.6.13","v3.7.10","v3.10.0a1","v3.6.12","v3.7.9","v3.9.0b5","v3.8.5","v3.7.8","v3.6.11","v3.6.11rc1","v3.7.8rc1","v3.9.0b3","v3.9.0b1","v3.8.3","v3.8.3rc1","v3.7.7rc1","v3.9.0a2","v3.6.10","v3.6.10rc1","v3.7.6rc1","v3.8.0rc1","v3.6.9","v3.6.9rc1","v3.7.3rc1","v3.6.8","v3.7.2rc1","v3.6.8rc1","v3.7.0rc1","v3.6.6rc1","v3.7.0b5","v3.7.0b4","v3.7.0b3","v3.7.0b2","v3.7.0b1","v3.7.0a2","v3.6.2rc1","v3.6.0rc1","v3.6.0b4","v3.6.0b3","v3.6.0b1","v3.6.0a3","v3.5.0b1","v3.5.0a4","v3.5.0a3","v3.5.0a2","v3.5.0a1","v3.4.0b3","v3.4.0b2","v3.4.0b1","v3.4.0a4","v3.4.0a3","v3.4.0a2","v3.4.0a1","v3.3.0rc3","v3.3.0rc2","v3.3.0rc1","v3.3.0b2","v3.3.0b1","v3.3.0a4","v3.3.0a3","v3.3.0a2","v3.2rc3","v3.2rc2","v3.2rc1","v3.2b2","v3.2b1","v3.2a4","v3.2a3","v3.2a2","v3.2a1","v3.1","v3.1rc2","v3.1rc1","v3.1b1","v3.1a2","v3.1a1","v3.0rc3","v3.0rc2","v3.0rc1","v3.0b3","v3.0b2","v3.0b1","v3.0a5","v3.0a4","v3.0a3","v3.0a2","v3.0a1","v2.4","v2.4c1","v2.4b2","v2.4b1","v2.4a3","v2.4a2","v2.4a1","v2.3c2","v2.3c1","v2.2a3","v2.1","v2.1c2","v2.1c1","v2.1b2","v2.1b1","v2.1a2","v2.1a1","v2.0","v2.0c1","v2.0b2","v2.0b1","v1.6a2","v1.6a1","v1.5.2","v1.5.2c1","v1.5.2b2","v1.5.2b1","v1.5.2a2","v1.5.2a1","v1.5.1","v1.5","v1.5b2","v1.5b1","v1.5a4","v1.5a3","v1.5a2","v1.5a1","v1.4","v1.4b3","v1.4b2","v1.4b1","v1.3","v1.3b1","v1.2","v1.2b4","v1.2b3","v1.2b2","v1.2b1","v1.1.1","v1.1","v1.0.2","v1.0.1","v0.9.9","v0.9.8"],"database_specific":{"source":"https://github.com/psf/advisory-database/blob/main/advisories/python/PSF-2022-6.json"}}],"schema_version":"1.7.5"}