CVE-2026-15806 (GCVE-0-2026-15806)

Vulnerability from cvelistv5 – Published: 2026-08-18 15:50 – Updated: 2026-10-02 00:39
VLAI
Title
`HTTPPasswordMgr` can send saved HTTPS credentials via HTTP because of incorrect scheme matching
Summary
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.
Severity
6 (Medium)
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
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-18 18:56 UTC
CWE
Assigner
PSF CNA under the mitre root
CNA scorecard B 80/100 over 28 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Python Software Foundation CPython Affected: 0 , < 3.10.22 (python)
Affected: 3.11.0 , < 3.11.17 (python)
Affected: 3.12.0 , < 3.12.15 (python)
Affected: 3.13.0 , < 3.13.16 (python)
Affected: 3.14.0 , < 3.14.8 (python)
Affected: 3.15.0a1 , < 3.15.0rc2 (python)
guessed Create a notification for this product.
Credits
Łukasz (https://github.com/lkk7) Kirill Podoprigora (https://github.com/Eclips4) Senthil Kumaran (https://github.com/orsenthil)
Show details on NVD website
To clipboard 

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              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "references": [
              {
                "tags": [
                  "exploit"
                ],
                "url": "https://github.com/python/cpython/issues/155694"
              }
            ],
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "CPython",
              "repo": "https://github.com/python/cpython",
              "vendor": "Python Software Foundation",
              "versions": [
                {
                  "lessThan": "3.10.22",
                  "status": "affected",
                  "version": "0",
                  "versionType": "python"
                },
                {
                  "lessThan": "3.11.17",
                  "status": "affected",
                  "version": "3.11.0",
                  "versionType": "python"
                },
                {
                  "lessThan": "3.12.15",
                  "status": "affected",
                  "version": "3.12.0",
                  "versionType": "python"
                },
                {
                  "lessThan": "3.13.16",
                  "status": "affected",
                  "version": "3.13.0",
                  "versionType": "python"
                },
                {
                  "lessThan": "3.14.8",
                  "status": "affected",
                  "version": "3.14.0",
                  "versionType": "python"
                },
                {
                  "lessThan": "3.15.0rc2",
                  "status": "affected",
                  "version": "3.15.0a1",
                  "versionType": "python"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "reporter",
              "value": "\u0141ukasz (https://github.com/lkk7)"
            },
            {
              "lang": "en",
              "type": "coordinator",
              "value": "Kirill Podoprigora (https://github.com/Eclips4)"
            },
            {
              "lang": "en",
              "type": "analyst",
              "value": "Senthil Kumaran (https://github.com/orsenthil)"
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "type": "text/html",
                  "value": "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://.\u003cbr\u003e\u003cbr\u003eCredential 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.\u003cbr\u003e\u003cbr\u003eUsers 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."
                }
              ],
              "value": "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."
            }
          ],
          "metrics": [
            {
              "cvssV4_0": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "HIGH",
                "attackRequirements": "PRESENT",
                "attackVector": "NETWORK",
                "baseScore": 6,
                "baseSeverity": "MEDIUM",
                "exploitMaturity": "NOT_DEFINED",
                "privilegesRequired": "NONE",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "NONE",
                "subIntegrityImpact": "NONE",
                "userInteraction": "PASSIVE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "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",
                "version": "4.0",
                "vulnAvailabilityImpact": "NONE",
                "vulnConfidentialityImpact": "HIGH",
                "vulnIntegrityImpact": "NONE",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-319",
                  "description": "CWE-319",
                  "lang": "en",
                  "type": "CWE"
                },
                {
                  "cweId": "CWE-522",
                  "description": "CWE-522",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-10-02T00:39:20.429Z",
            "orgId": "28c92f92-d60d-412d-b760-e73465c3df22",
            "shortName": "PSF"
          },
          "references": [
            {
              "tags": [
                "issue-tracking"
              ],
              "url": "https://github.com/python/cpython/issues/155694"
            },
            {
              "tags": [
                "patch"
              ],
              "url": "https://github.com/python/cpython/pull/155696"
            },
            {
              "tags": [
                "vendor-advisory"
              ],
              "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/3OKPE5S75KDNA7FY7AI3PL2MXM2X5RB3/"
            },
            {
              "tags": [
                "patch"
              ],
              "url": "https://github.com/python/cpython/commit/a0d023fbd23773e24b35d8368789470e22cda5d8"
            },
            {
              "tags": [
                "patch"
              ],
              "url": "https://github.com/python/cpython/commit/a2773a34183b7d94a243bb98fd658926cc5348ce"
            },
            {
              "tags": [
                "patch"
              ],
              "url": "https://github.com/python/cpython/commit/a7bb524fef61f77ede01f660ffbd591e1d5837ce"
            },
            {
              "tags": [
                "patch"
              ],
              "url": "https://github.com/python/cpython/commit/641be42bb07921ba0f8bffe228b1dc706b092ef6"
            },
            {
              "tags": [
                "patch"
              ],
              "url": "https://github.com/python/cpython/commit/851cf9a7142ecbdd39f831055533f58284ad2bcc"
            },
            {
              "tags": [
                "patch"
              ],
              "url": "https://github.com/python/cpython/commit/95355ee3a8e1d3c3d4858d1973aa42a9b91a2801"
            },
            {
              "tags": [
                "patch"
              ],
              "url": "https://github.com/python/cpython/commit/dac88d8615078c55f1304ea4c7a2d822700d4e5a"
            }
          ],
          "source": {
            "discovery": "UNKNOWN"
          },
          "title": "`HTTPPasswordMgr` can send saved HTTPS credentials via HTTP because of incorrect scheme matching",
          "x_generator": {
            "engine": "cvelib 1.8.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "28c92f92-d60d-412d-b760-e73465c3df22",
        "assignerShortName": "PSF",
        "cveId": "CVE-2026-15806",
        "datePublished": "2026-08-18T15:50:57.983Z",
        "dateReserved": "2026-07-15T08:49:13.390Z",
        "dateUpdated": "2026-10-02T00:39:20.429Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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