{"id":"USN-8556-1","summary":"ruby2.3 vulnerabilities","details":"It was discovered that the Net::IMAP client in Ruby did not properly\nsanitize Symbol arguments passed to IMAP commands. A remote attacker\ncontrolling a malicious IMAP server, or able to influence command\narguments, could use this to inject arbitrary IMAP commands via CRLF\nsequences. (CVE-2026-42258)\n\nIt was discovered that the Zlib::GzipReader in Ruby did not correctly\nensure sufficient buffer capacity in the zstream_buffer_ungets function.\nAn attacker could use this to craft a gzip stream that, when processed,\ncould cause a buffer overflow, resulting in memory corruption and possibly\narbitrary code execution. (CVE-2026-27820)","modified":"2026-07-16T20:50:07.019752885Z","published":"2026-07-16T13:54:42Z","related":["UBUNTU-CVE-2026-27820","UBUNTU-CVE-2026-42258"],"upstream":["CVE-2026-27820","CVE-2026-42258","UBUNTU-CVE-2026-27820","UBUNTU-CVE-2026-42258"],"references":[{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8556-1"},{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-27820"},{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-42258"}],"affected":[{"package":{"name":"ruby2.3","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/ruby2.3?arch=source&distro=esm-infra-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.1-2~ubuntu16.04.16+esm15"}]}],"versions":["2.3.0-1","2.3.0-2","2.3.0-4ubuntu2","2.3.0-4ubuntu3","2.3.0-5ubuntu1","2.3.1-2~16.04","2.3.1-2~16.04.2","2.3.1-2~16.04.4","2.3.1-2~16.04.5","2.3.1-2~16.04.6","2.3.1-2~16.04.7","2.3.1-2~16.04.9","2.3.1-2~16.04.10","2.3.1-2~16.04.11","2.3.1-2~16.04.12","2.3.1-2~ubuntu16.04.13","2.3.1-2~ubuntu16.04.14","2.3.1-2~ubuntu16.04.15","2.3.1-2~ubuntu16.04.16","2.3.1-2~ubuntu16.04.16+esm1","2.3.1-2~ubuntu16.04.16+esm2","2.3.1-2~ubuntu16.04.16+esm3","2.3.1-2~ubuntu16.04.16+esm4","2.3.1-2~ubuntu16.04.16+esm5","2.3.1-2~ubuntu16.04.16+esm6","2.3.1-2~ubuntu16.04.16+esm7","2.3.1-2~ubuntu16.04.16+esm8","2.3.1-2~ubuntu16.04.16+esm9","2.3.1-2~ubuntu16.04.16+esm10","2.3.1-2~ubuntu16.04.16+esm11","2.3.1-2~ubuntu16.04.16+esm12","2.3.1-2~ubuntu16.04.16+esm14"],"ecosystem_specific":{"binaries":[{"binary_name":"libruby2.3","binary_version":"2.3.1-2~ubuntu16.04.16+esm15"},{"binary_name":"ruby2.3","binary_version":"2.3.1-2~ubuntu16.04.16+esm15"},{"binary_version":"2.3.1-2~ubuntu16.04.16+esm15","binary_name":"ruby2.3-tcltk"}],"availability":"Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"},"database_specific":{"cves_map":{"cves":[{"severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U"},{"score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","type":"CVSS_V3"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-27820"},{"id":"CVE-2026-42258","severity":[{"score":"CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N","type":"CVSS_V4"},{"score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N","type":"CVSS_V3"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L"},{"score":"medium","type":"Ubuntu"}]}],"ecosystem":"Ubuntu:Pro:16.04:LTS"},"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8556-1.json"}}],"schema_version":"1.7.5"}