Python 2.7.x through 2.7.16 and 3.x through 3.7.2 is affected by: Improper Handling of Unicode Encoding (with an incorrect netloc) during NFKC normalization. The impact is: Information disclosure (credentials cookies etc. that are cached against a given hostname). The components are: urllib.parse.urlsplit urllib.parse.urlparse. The attack vector is: A specially crafted URL could be incorrectly parsed to locate cookies or authentication data and send that information to a different host than when parsed correctly. This is fixed in: v2.7.17 v2.7.17rc1 v2.7.18 v2.7.18rc1; v3.5.10 v3.5.10rc1 v3.5.7 v3.5.8 v3.5.8rc1 v3.5.8rc2 v3.5.9; v3.6.10 v3.6.10rc1 v3.6.11 v3.6.11rc1 v3.6.12 v3.6.9 v3.6.9rc1; v3.7.3 v3.7.3rc1 v3.7.4 v3.7.4rc1 v3.7.4rc2 v3.7.5 v3.7.5rc1 v3.7.6 v3.7.6rc1 v3.7.7 v3.7.7rc1 v3.7.8 v3.7.8rc1 v3.7.9.