{"id":"UBUNTU-CVE-2021-3657","details":"A flaw was found in mbsync versions prior to 1.4.4. Due to inadequate handling of extremely large (\u003e=2GiB) IMAP literals, malicious or compromised IMAP servers, and hypothetically even external email senders, could cause several different buffer overflows, which could conceivably be exploited for remote code execution.","modified":"2026-05-20T16:05:04.823888039Z","published":"2022-02-18T18:15:00Z","upstream":["CVE-2021-3657"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-3657"},{"type":"REPORT","url":"https://www.openwall.com/lists/oss-security/2021/12/03/1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-3657"}],"affected":[{"package":{"name":"isync","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/isync?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.1.2-1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.1.2-1","binary_name":"isync"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3657.json"}},{"package":{"name":"isync","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/isync?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.1-2","1.3.0-1","1.3.0-1build1","1.3.0-1ubuntu0.18.04.0"],"ecosystem_specific":{"binaries":[{"binary_version":"1.3.0-1ubuntu0.18.04.0","binary_name":"isync"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3657.json"}},{"package":{"name":"isync","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/isync?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0-2"],"ecosystem_specific":{"binaries":[{"binary_version":"1.3.0-2","binary_name":"isync"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3657.json"}},{"package":{"name":"isync","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/isync?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0-2.2","1.4.3-1","1.4.4-1","1.4.4-3","1.4.4-3ubuntu0.22.04.1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.4.4-3ubuntu0.22.04.1","binary_name":"isync"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3657.json"}},{"package":{"name":"isync","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/isync?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.4.4-5","1.4.4-5build2","1.4.4-5build3"],"ecosystem_specific":{"binaries":[{"binary_name":"isync","binary_version":"1.4.4-5build3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3657.json"}},{"package":{"name":"isync","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/isync?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.4.4-5build3","1.5.1-1ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"isync","binary_version":"1.5.1-1ubuntu1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3657.json"}},{"package":{"name":"isync","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/isync?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.1-1ubuntu1","1.5.1-1ubuntu2"],"ecosystem_specific":{"binaries":[{"binary_version":"1.5.1-1ubuntu2","binary_name":"isync"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3657.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:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}]}