{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-27448", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-02-19T17:25:31.100Z", "datePublished": "2026-03-17T23:24:30.661Z", "dateUpdated": "2026-03-18T20:18:08.768Z"}, "containers": {"cna": {"title": "pyOpenSSL allows TLS connection bypass via unhandled callback exception in set_tlsext_servername_callback", "problemTypes": [{"descriptions": [{"cweId": "CWE-636", "lang": "en", "description": "CWE-636: Not Failing Securely ('Failing Open')", "type": "CWE"}]}], "metrics": [{"cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 1.7, "baseSeverity": "LOW", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U", "version": "4.0"}}], "references": [{"name": "https://github.com/pyca/pyopenssl/security/advisories/GHSA-vp96-hxj8-p424", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/pyca/pyopenssl/security/advisories/GHSA-vp96-hxj8-p424"}, {"name": "https://github.com/pyca/pyopenssl/commit/d41a814759a9fb49584ca8ab3f7295de49a85aa0", "tags": ["x_refsource_MISC"], "url": "https://github.com/pyca/pyopenssl/commit/d41a814759a9fb49584ca8ab3f7295de49a85aa0"}, {"name": "https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst#L27", "tags": ["x_refsource_MISC"], "url": "https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst#L27"}], "affected": [{"vendor": "pyca", "product": "pyopenssl", "versions": [{"version": ">= 0.14.0, < 26.0.0", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-03-17T23:24:30.661Z"}, "descriptions": [{"lang": "en", "value": "pyOpenSSL is a Python wrapper around the OpenSSL library. Starting in version 0.14.0 and prior to version 26.0.0, if a user provided callback to `set_tlsext_servername_callback` raised an unhandled exception, this would result in a connection being accepted. If a user was relying on this callback for any security-sensitive behavior, this could allow bypassing it. Starting in version 26.0.0, unhandled exceptions now result in rejecting the connection."}], "source": {"advisory": "GHSA-vp96-hxj8-p424", "discovery": "UNKNOWN"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-03-18T20:17:52.492201Z", "id": "CVE-2026-27448", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-03-18T20:18:08.768Z"}}]}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "pyOpenSSL is a Python wrapper around the OpenSSL library. Starting in version 0.14.0 and prior to version 26.0.0, if a user provided callback to `set_tlsext_servername_callback` raised an unhandled exception, this would result in a connection being accepted. If a user was relying on this callback for any security-sensitive behavior, this could allow bypassing it. Starting in version 26.0.0, unhandled exceptions now result in rejecting the connection."}, {"lang": "es", "value": "pyOpenSSL es un envoltorio de Python alrededor de la biblioteca OpenSSL. A partir de la versi\u00f3n 0.14.0 y antes de la versi\u00f3n 26.0.0, si un callback proporcionado por el usuario a `set_tlsext_servername_callback` generaba una excepci\u00f3n no controlada, esto daba como resultado que se aceptara una conexi\u00f3n. Si un usuario depend\u00eda de este callback para cualquier comportamiento sensible a la seguridad, esto podr\u00eda permitir eludirlo. A partir de la versi\u00f3n 26.0.0, las excepciones no controladas ahora dan como resultado el rechazo de la conexi\u00f3n."}], "id": "CVE-2026-27448", "lastModified": "2026-03-18T14:52:44.227", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 1.7, "baseSeverity": "LOW", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "UNREPORTED", "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:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/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": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-03-18T00:16:19.107", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst#L27"}, {"source": "security-advisories@github.com", "url": "https://github.com/pyca/pyopenssl/commit/d41a814759a9fb49584ca8ab3f7295de49a85aa0"}, {"source": "security-advisories@github.com", "url": "https://github.com/pyca/pyopenssl/security/advisories/GHSA-vp96-hxj8-p424"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Undergoing Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-636"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0.14.0,26.0.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "cna", "scores": [{"score": 100.0, "source": "cna"}]}, "original": {"product": "pyopenssl", "source": "cna", "vendor": "pyca"}, "product": "pyopenssl", "vendor": "pyca"}], "created": "2026-03-18T10:42:33.089614+00:00", "updated": "2026-03-18T10:42:33.089687+00:00", "vendors": ["pyca", "pyca$PRODUCT$pyopenssl"]}