{"id":"PSF-2019-13","summary":"ssl.match_hostname() ignores extra string after whitespace in IPv4 address","details":"``inet_aton()`` accepts trailing characters after a valid IP.  Because of\nthat, Python ``ssl.match_hostname('1.1.1.1 ; this should not work but does')``\nsucceeded when it should fail.\n\nThe issue was introduced in `bpo-32819\n\u003chttps://bugs.python.org/issue32819\u003e`_ by `commit aef1283b\n\u003chttps://github.com/python/cpython/commit/aef1283ba428e33397d87cee3c54a5110861552d\u003e`_.\nOnly Python 3.7 and newer are affected. It's a potential security bug\nalthough **low severity**. For one Python 3.7 and newer **no longer use**\n``ssl.match_hostname()`` to verify hostnames and IP addresses of a\ncertificate: **matching is performed by OpenSSL**.\n\nIt should not possible to register a x509 certificate with a hostname with\nspaces.\n\nThe glibc function ``inet_aton()`` accepts input as valid if said input is\na IPv4 address followed by zero or more characters that are valid\nwhite-space as decided by ``isspace()``, with the rest of the string after\nthe first white-space being ignored. As ``'\\r'`` is a valid white-space\ncharacter the rest of the string is ignored (including the ``'\\r'``). See\n`glibc bug 24111: Deprecate inet_addr, inet_aton\n\u003chttps://sourceware.org/bugzilla/show_bug.cgi?id=24111\u003e`_.\n","modified":"2025-10-09T01:00:18.071323Z","published":"2019-07-01T00:00:00Z","database_specific":{"cwe_ids":[]},"references":[{"type":"REPORT","url":"https://bugs.python.org/issue37463"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/python/cpython","events":[{"introduced":"0"},{"fixed":"070fae6d0ff49e63bfd5f2bdc66f8eb1df3b6557"},{"fixed":"3cba3d3c55f230a59174a0dfcafb1d4685269e60"},{"fixed":"477b1b25768945621d466a8b3f0739297a842439"}]}],"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","v3.1a1","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","v3.7.0a2","v3.7.0a3","v3.7.0a4","v3.8.0a1","v3.8.0a2","v3.8.0a3","v3.8.0a4","v3.8.0b1"],"database_specific":{"source":"https://github.com/psf/advisory-database/blob/main/advisories/python/PSF-2019-13.json"}}],"schema_version":"1.7.3"}