CVE-2026-15806

{"id": "CVE-2026-15806", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-15806", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-18T18:56:36.349726Z"}}], "cvssMetricV40": [{"type": "Secondary", "source": "cna@python.org", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 6.0, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "PASSIVE", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "cna@python.org", "affectedData": [{"repo": "https://github.com/python/cpython", "vendor": "Python Software Foundation", "product": "CPython", "versions": [{"status": "affected", "version": "0", "lessThan": "3.15.0rc2", "versionType": "python"}], "defaultStatus": "unaffected"}]}], "published": "2026-08-18T16:17:02.220", "references": [{"url": "https://github.com/python/cpython/commit/641be42bb07921ba0f8bffe228b1dc706b092ef6", "source": "cna@python.org"}, {"url": "https://github.com/python/cpython/commit/851cf9a7142ecbdd39f831055533f58284ad2bcc", "source": "cna@python.org"}, {"url": "https://github.com/python/cpython/commit/a0d023fbd23773e24b35d8368789470e22cda5d8", "source": "cna@python.org"}, {"url": "https://github.com/python/cpython/commit/a2773a34183b7d94a243bb98fd658926cc5348ce", "source": "cna@python.org"}, {"url": "https://github.com/python/cpython/commit/a7bb524fef61f77ede01f660ffbd591e1d5837ce", "source": "cna@python.org"}, {"url": "https://github.com/python/cpython/issues/155694", "source": "cna@python.org"}, {"url": "https://github.com/python/cpython/pull/155696", "source": "cna@python.org"}, {"url": "https://mail.python.org/archives/list/security-announce@python.org/thread/3OKPE5S75KDNA7FY7AI3PL2MXM2X5RB3/", "source": "cna@python.org"}, {"url": "http://www.openwall.com/lists/oss-security/2026/08/18/3", "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://github.com/python/cpython/issues/155694", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "cna@python.org", "description": [{"lang": "en", "value": "CWE-319"}, {"lang": "en", "value": "CWE-522"}]}], "descriptions": [{"lang": "en", "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."}], "lastModified": "2026-09-02T01:17:23.350", "sourceIdentifier": "cna@python.org"}