BIT-python-2026-15806

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    BIT-python-2026-15806

    Published: 11 Sept 2026Last Modified: 11 Sept 2026

    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://. Credential 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. Users 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.

    References: http://www.openwall.com/lists/oss-security/2026/08/18/3, https://github.com/python/cpython/commit/641be42bb07921ba0f8bffe228b1dc706b092ef6, https://github.com/python/cpython/commit/851cf9a7142ecbdd39f831055533f58284ad2bcc, https://github.com/python/cpython/commit/a0d023fbd23773e24b35d8368789470e22cda5d8, https://github.com/python/cpython/commit/a2773a34183b7d94a243bb98fd658926cc5348ce, https://github.com/python/cpython/commit/a7bb524fef61f77ede01f660ffbd591e1d5837ce, https://github.com/python/cpython/issues/155694, https://github.com/python/cpython/pull/155696, https://mail.python.org/archives/list/[email protected]/thread/3OKPE5S75KDNA7FY7AI3PL2MXM2X5RB3/, https://nvd.nist.gov/vuln/detail/CVE-2026-15806

    Affected packages

    Package

    Name: python

    Purl: pkg:bitnami/python

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High