{"id":"UBUNTU-CVE-2026-56741","details":"JLine is a Java library for handling console input. Prior to 3.30.14, 4.0.16, and 4.2.1, the JLine3 Telnet server remote-telnet module does not apply an upper bound to terminal dimensions received via the Telnet NAWS option, and TelnetIO.handleNAWS() in TelnetIO.java:856-879 reads client-supplied width and height as 16-bit unsigned integers and passes values such as 65535x65535 to setTerminalGeometry(), allowing an unauthenticated remote attacker to repeatedly alternate values and trigger continuous expensive rendering work that causes CPU exhaustion and denial of service. This issue is fixed in versions 3.30.14, 4.0.16, and 4.2.1.","modified":"2026-07-29T10:18:39.029036366Z","published":"2026-07-17T22:17:00Z","upstream":["CVE-2026-56741"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-56741"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-56741"},{"type":"REPORT","url":"https://github.com/jline/jline3/security/advisories/GHSA-2r2c-cx56-8933"},{"type":"REPORT","url":"https://github.com/jline/jline3/pull/2000"}],"affected":[{"package":{"name":"jline","ecosystem":"Ubuntu:14.04:LTS","purl":"pkg:deb/ubuntu/jline?arch=source&distro=trusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"libjline-java","binary_version":"1.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56741.json"}},{"package":{"name":"jline2","ecosystem":"Ubuntu:14.04:LTS","purl":"pkg:deb/ubuntu/jline2?arch=source&distro=trusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.11-1","2.11-2"],"ecosystem_specific":{"binaries":[{"binary_name":"libjline2-java","binary_version":"2.11-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56741.json"}},{"package":{"name":"jline","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/jline?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"libjline-java","binary_version":"1.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56741.json"}},{"package":{"name":"jline2","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/jline2?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.11-4"],"ecosystem_specific":{"binaries":[{"binary_version":"2.11-4","binary_name":"libjline2-java"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56741.json"}},{"package":{"name":"jline","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/jline?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"libjline-java","binary_version":"1.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56741.json"}},{"package":{"name":"jline2","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/jline2?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.11-4","2.12.1-1","2.14.6-1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.14.6-1","binary_name":"libjline2-java"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56741.json"}},{"package":{"name":"jline","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/jline?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"libjline-java","binary_version":"1.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56741.json"}},{"package":{"name":"jline2","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/jline2?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.14.6-3"],"ecosystem_specific":{"binaries":[{"binary_name":"libjline2-java","binary_version":"2.14.6-3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56741.json"}},{"package":{"name":"jline","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/jline?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0-3"],"ecosystem_specific":{"binaries":[{"binary_version":"1.0-3","binary_name":"libjline-java"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56741.json"}},{"package":{"name":"jline2","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/jline2?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.14.6-4"],"ecosystem_specific":{"binaries":[{"binary_version":"2.14.6-4","binary_name":"libjline2-java"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56741.json"}},{"package":{"name":"jline3","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/jline3?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.3.1-2"],"eco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