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`HTTPPasswordMgr` can send saved HTTPS credentials via HTTP because of incorrect scheme matching

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-15806

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-15806

CPython

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://github.com/python/cpython",
    "vendor": "Python Software Foundation",
    "product": "CPython",
    "versions": [
      {
        "status": "affected",
        "version": "0",
        "lessThan": "3.10.22",
        "versionType": "python"
      },
      {
        "status": "affected",
        "version": "3.11.0",
        "lessThan": "3.11.17",
        "versionType": "python"
      },
      {
        "status": "affected",
        "version": "3.12.0",
        "lessThan": "3.12.15",
        "versionType": "python"
      },
      {
        "status": "affected",
        "version": "3.13.0",
        "lessThan": "3.13.16",
        "versionType": "python"
      },
      {
        "status": "affected",
        "version": "3.14.0",
        "lessThan": "3.14.8",
        "versionType": "python"
      },
      {
        "status": "affected",
        "version": "3.15.0a1",
        "lessThan": "3.15.0rc2",
        "versionType": "python"
      }
    ],
    "defaultStatus": "unaffected"
  }
]
Related CVEs
CVE-2026-15806

Source reference: /cveMetadata/cveId

Publisher severity

medium

Source reference: /containers/cna/metrics

Event
#7814 · Revision 1
Added to Heist Feed
Publisher date
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