{"id":"UBUNTU-CVE-2020-36843","details":"The implementation of EdDSA in EdDSA-Java (aka ed25519-java) through 0.3.0 exhibits signature malleability and does not satisfy the SUF-CMA (Strong Existential Unforgeability under Chosen Message Attacks) property. This allows attackers to create new valid signatures different from previous signatures for a known message.","modified":"2026-05-20T16:04:34.118577585Z","published":"2025-03-13T06:15:00Z","upstream":["CVE-2020-36843"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2020-36843"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2020-36843"},{"type":"REPORT","url":"https://eprint.iacr.org/2020/1244"},{"type":"REPORT","url":"https://github.com/str4d/ed25519-java/issues/82#issue-727629226"}],"affected":[{"package":{"name":"ruby-ed25519","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/ruby-ed25519?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.4-1","1.2.4-1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-ed25519","binary_version":"1.2.4-1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-36843.json"}},{"package":{"name":"ruby-ed25519","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/ruby-ed25519?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.4-2","1.2.4-2build1","1.3.0+ds-1"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-ed25519","binary_version":"1.3.0+ds-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-36843.json"}},{"package":{"name":"ruby-ed25519","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/ruby-ed25519?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0+ds-1build2","1.3.0+ds-1build3","1.3.0+ds-1build4"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-ed25519","binary_version":"1.3.0+ds-1build4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-36843.json"}},{"package":{"name":"libeddsa-java","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/libeddsa-java?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.3.0-2","0.3.0-2.1"],"ecosystem_specific":{"binaries":[{"binary_name":"libeddsa-java","binary_version":"0.3.0-2.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-36843.json"}},{"package":{"name":"ruby-ed25519","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/ruby-ed25519?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0+ds-1build5","1.4.0+ds-1"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-ed25519","binary_version":"1.4.0+ds-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-36843.json"}},{"package":{"name":"libeddsa-java","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/libeddsa-java?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.3.0-2.1","0.3.0-3"],"ecosystem_specific":{"binaries":[{"binary_name":"libeddsa-java","binary_version":"0.3.0-3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-36843.json"}},{"package":{"name":"ruby-ed25519","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/ruby-ed25519?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.4.0+ds-1"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-ed25519","binary_version":"1.4.0+ds-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-36843.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N"},{"type":"Ubuntu","score":"medium"}]}