{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-19445", "assignerOrgId": "28c92f92-d60d-412d-b760-e73465c3df22", "state": "PUBLISHED", "assignerShortName": "PSF", "dateReserved": "2026-08-10T13:31:21.724Z", "datePublished": "2026-09-30T16:16:04.923Z", "dateUpdated": "2026-09-30T16:16:04.923Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "modules": ["ssl"], "product": "CPython", "repo": "https://github.com/python/cpython", "vendor": "Python Software Foundation", "versions": [{"lessThan": "3.16.0", "status": "affected", "version": "0", "versionType": "python"}]}], "credits": [{"lang": "en", "type": "reporter", "value": "Gregory P. Smith (https://github.com/gpshead)"}, {"lang": "en", "type": "coordinator", "value": "Seth Larson (https://github.com/sethmlarson)"}, {"lang": "en", "type": "remediation reviewer", "value": "B\u00e9n\u00e9dikt Tran (https://github.com/picnixz)"}], "descriptions": [{"lang": "en", "supportingMedia": [{"type": "text/html", "value": "<p>A remote, unauthenticated TLS client can make a server crash or call\nthrough a freed pointer if its sni_callback assigns a different context to\nSSLSocket.context (the documented way to select a certificate per server\nname) and nothing else keeps the original ssl.SSLContext alive. Typical\ncases are servers that create an SSLContext per connection or replace it\nwhile connections are open; servers that wrap their listening socket with\nit are not affected.</p>\n<p>Mitigation: keep a reference to every SSLContext that sets sni_callback for\nthe lifetime of the server. TLS clients are not affected.</p>"}], "value": "A remote, unauthenticated TLS client can make a server crash or call\nthrough a freed pointer if its sni_callback assigns a different context to\nSSLSocket.context (the documented way to select a certificate per server\nname) and nothing else keeps the original ssl.SSLContext alive. Typical\ncases are servers that create an SSLContext per connection or replace it\nwhile connections are open; servers that wrap their listening socket with\nit are not affected.\n\n\nMitigation: keep a reference to every SSLContext that sets sni_callback for\nthe lifetime of the server. TLS clients are not affected."}], "metrics": [{"cvssV4_0": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "baseScore": 9.2, "baseSeverity": "CRITICAL", "exploitMaturity": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N", "version": "4.0", "vulnAvailabilityImpact": "LOW", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-416", "description": "CWE-416", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "28c92f92-d60d-412d-b760-e73465c3df22", "shortName": "PSF", "dateUpdated": "2026-09-30T16:16:04.923Z"}, "references": [{"tags": ["patch"], "url": "https://github.com/python/cpython/pull/158504"}, {"tags": ["vendor-advisory"], "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/QMQIUQB6WGGC3MI7I3WKQXOYOBDSPPS3/"}, {"tags": ["issue-tracking"], "url": "https://github.com/python/cpython/issues/156293"}], "source": {"discovery": "UNKNOWN"}, "title": "Use-after-free of a server-side SSLContext when sni_callback switches contexts"}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "modules": ["ssl"], "product": "CPython", "repo": "https://github.com/python/cpython", "vendor": "Python Software Foundation", "versions": [{"lessThan": "3.16.0", "status": "affected", "version": "0", "versionType": "python"}]}], "source": "cna@python.org"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "A remote, unauthenticated TLS client can make a server crash or call\nthrough a freed pointer if its sni_callback assigns a different context to\nSSLSocket.context (the documented way to select a certificate per server\nname) and nothing else keeps the original ssl.SSLContext alive. Typical\ncases are servers that create an SSLContext per connection or replace it\nwhile connections are open; servers that wrap their listening socket with\nit are not affected.\n\n\nMitigation: keep a reference to every SSLContext that sets sni_callback for\nthe lifetime of the server. TLS clients are not affected."}], "id": "CVE-2026-19445", "lastModified": "2026-09-30T17:31:44.573", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 9.2, "baseSeverity": "CRITICAL", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/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", "version": "4.0", "vulnAvailabilityImpact": "LOW", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "cna@python.org", "type": "Secondary"}]}, "published": "2026-09-30T17:16:45.720", "references": [{"source": "cna@python.org", "url": "https://github.com/python/cpython/issues/156293"}, {"source": "cna@python.org", "url": "https://github.com/python/cpython/pull/158504"}, {"source": "cna@python.org", "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/QMQIUQB6WGGC3MI7I3WKQXOYOBDSPPS3/"}], "sourceIdentifier": "cna@python.org", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "cna@python.org", "type": "Secondary"}]}

{}

{"created": "2026-09-30T17:30:19.266398+00:00", "updated": "2026-09-30T17:30:19.266403+00:00", "vendors": []}