{"id":"UBUNTU-CVE-2020-36478","details":"An issue was discovered in Mbed TLS before 2.25.0 (and before 2.16.9 LTS and before 2.7.18 LTS). A NULL algorithm parameters entry looks identical to an array of REAL (size zero) and thus the certificate is considered valid. However, if the parameters do not match in any way, then the certificate should be considered invalid.","modified":"2026-04-22T14:27:04.771672Z","published":"2021-08-23T02:15:00Z","upstream":["CVE-2020-36478"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2020-36478"},{"type":"REPORT","url":"https://github.com/ARMmbed/mbedtls/issues/3629"},{"type":"REPORT","url":"https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.9"},{"type":"REPORT","url":"https://github.com/ARMmbed/mbedtls/releases/tag/v2.25.0"},{"type":"REPORT","url":"https://github.com/ARMmbed/mbedtls/releases/tag/v2.7.18"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2020-36478"}],"affected":[{"package":{"name":"mbedtls","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/mbedtls@2.2.1-2ubuntu0.3?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.1.2-1","2.2.0-1","2.2.1-1","2.2.1-2","2.2.1-2ubuntu0.1","2.2.1-2ubuntu0.2","2.2.1-2ubuntu0.3"],"ecosystem_specific":{"binaries":[{"binary_name":"libmbedcrypto0","binary_version":"2.2.1-2ubuntu0.3"},{"binary_name":"libmbedtls10","binary_version":"2.2.1-2ubuntu0.3"},{"binary_name":"libmbedx509-0","binary_version":"2.2.1-2ubuntu0.3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-36478.json"}},{"package":{"name":"mbedtls","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/mbedtls@2.8.0-1ubuntu0.1~esm1?arch=source&distro=esm-apps/bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.5.1-1ubuntu1","2.6.0-1","2.7.0-2","2.8.0-1","2.8.0-1ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libmbedcrypto1","binary_version":"2.8.0-1ubuntu0.1~esm1"},{"binary_name":"libmbedtls10","binary_version":"2.8.0-1ubuntu0.1~esm1"},{"binary_name":"libmbedx509-0","binary_version":"2.8.0-1ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-36478.json"}},{"package":{"name":"mbedtls","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/mbedtls@2.16.4-1ubuntu2+esm1?arch=source&distro=esm-apps/focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.16.2-1","2.16.3-1","2.16.4-1ubuntu2","2.16.4-1ubuntu2+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libmbedcrypto3","binary_version":"2.16.4-1ubuntu2+esm1"},{"binary_name":"libmbedtls12","binary_version":"2.16.4-1ubuntu2+esm1"},{"binary_name":"libmbedx509-0","binary_version":"2.16.4-1ubuntu2+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-36478.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}