{"id":"CVE-2026-15806","summary":"`HTTPPasswordMgr` can send saved HTTPS credentials via HTTP because of incorrect scheme matching","details":"The HTTPPasswordMgr class in the urllib.request module, along with its subclasses HTTPPasswordMgrWithDefaultRealm and HTTPPasswordMgrWithPriorAuth, did not take the URL scheme into account when matching stored credentials against a requested URL. Credentials added for an https:// URL were also used for requests to the same host over http://, so an attacker able to redirect or downgrade a client to plain HTTP (for example, via an HTTPS-to-HTTP redirect or an on-path position) could capture credentials in cleartext. Credentials added for http:// URLs could likewise be sent over https://.\n\nCredential matching is now scoped by URL scheme. Credentials registered with a URL that includes a scheme are only used for requests with the same scheme. Credentials registered with a bare authority (such as example.com or example.com:8080) continue to match any scheme, preserving compatibility with existing code, including proxy authentication.\n\nUsers who cannot upgrade immediately can mitigate by ensuring that applications never make plain http:// requests to hosts for which credentials are registered, for example by not following redirects to http:// URLs.","aliases":["PSF-2026-36"],"modified":"2026-08-21T11:47:36.639352148Z","published":"2026-08-18T15:50:57.983Z","database_specific":{"unresolved_ranges":[{"source":"AFFECTED_FIELD","extracted_events":[{"fixed":"3.15.0"}]}],"cna_assigner":"PSF","cwe_ids":["CWE-319","CWE-522"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/15xxx/CVE-2026-15806.json"},"references":[{"type":"WEB","url":"http://www.openwall.com/lists/oss-security/2026/08/18/3"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/15xxx/CVE-2026-15806.json"},{"type":"ADVISORY","url":"https://mail.python.org/archives/list/security-announce@python.org/thread/3OKPE5S75KDNA7FY7AI3PL2MXM2X5RB3/"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-15806"},{"type":"REPORT","url":"https://github.com/python/cpython/issues/155694"},{"type":"FIX","url":"https://github.com/python/cpython/commit/641be42bb07921ba0f8bffe228b1dc706b092ef6"},{"type":"FIX","url":"https://github.com/python/cpython/commit/851cf9a7142ecbdd39f831055533f58284ad2bcc"},{"type":"FIX","url":"https://github.com/python/cpython/commit/a0d023fbd23773e24b35d8368789470e22cda5d8"},{"type":"FIX","url":"https://github.com/python/cpython/commit/a2773a34183b7d94a243bb98fd658926cc5348ce"},{"type":"FIX","url":"https://github.com/python/cpython/commit/a7bb524fef61f77ede01f660ffbd591e1d5837ce"},{"type":"FIX","url":"https://github.com/python/cpython/pull/155696"},{"type":"PACKAGE","url":"https://github.com/python/cpython"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/python/cpython","events":[{"introduced":"0"},{"fixed":"641be42bb07921ba0f8bffe228b1dc706b092ef6"},{"fixed":"a0d023fbd23773e24b35d8368789470e22cda5d8"},{"fixed":"a2773a34183b7d94a243bb98fd658926cc5348ce"},{"fixed":"a7bb524fef61f77ede01f660ffbd591e1d5837ce"}],"database_specific":{"source":"REFERENCES"}}],"versions":["v3.13.15","v3.14.7","v3.15.0rc1","v3.15.0b4","v3.15.0b3","v3.13.14","v3.14.6","v3.15.0b2","v3.14.5","v3.15.0b1","v3.14.5rc1","v3.13.13","v3.14.4","v3.15.0a8","v3.15.0a7","v3.15.0a6","v3.13.12","v3.14.3","v3.15.0a5","v3.15.0a4","v3.15.0a3","v3.14.2","v3.13.11","v3.13.10","v3.14.1","v3.15.0a2","v3.15.0a1","v3.13.8","v3.14.0","v3.14.0rc3","v3.13.7","v3.14.0rc2","v3.13.6","v3.14.0rc1","v3.14.0b4","v3.14.0b3","v3.13.5","v3.13.4","v3.14.0b2","v3.14.0b1","v3.13.3","v3.14.0a7","v3.14.0a6","v3.14.0a5","v3.13.2","v3.14.0a4","v3.14.0a3","v3.13.1","v3.14.0a2","v3.14.0a1","v3.13.0","v3.13.0rc3","v3.13.0rc2","v3.13.0rc1","v3.13.0b4","v3.13.0b3","v3.13.0b2","v3.13.0b1","v3.13.0a6","v3.13.0a5","v3.13.0a4","v3.13.0a3","v3.13.0a2","v3.13.0a1","v3.12.0b1","v3.12.0a7","v3.12.0a6","v3.12.0a5","v3.12.0a4","v3.12.0a3","v3.12.0a2","v3.12.0a1","v3.11.0b1","v3.11.0a7","v3.11.0a6","v3.11.0a5","v3.11.0a4","v3.11.0a3","v3.10.0a7","v3.10.0a1","v3.9.0a2","v3.7.0a2","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://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-15806.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"}]}