{"id":"USN-8954-1","summary":"zlib vulnerability","details":"Ali Firas discovered that zlib incorrectly handled certain non-blocking\nwrite operations. An attacker could possibly use this issue to trigger a\nheap buffer overflow, resulting in a denial of service or arbitrary code\nexecution.","modified":"2026-10-23T04:58:08.237439926Z","published":"2026-10-22T19:54:53Z","related":["UBUNTU-CVE-2026-85091"],"upstream":["CVE-2026-85091","UBUNTU-CVE-2026-85091"],"references":[{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8954-1"},{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-85091"}],"affected":[{"package":{"name":"zlib","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/zlib?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:1.3.dfsg-3.1ubuntu2.3"}]}],"versions":["1:1.2.13.dfsg-1ubuntu5","1:1.3.dfsg-3ubuntu1","1:1.3.dfsg-3.1ubuntu1","1:1.3.dfsg-3.1ubuntu2","1:1.3.dfsg-3.1ubuntu2.1","1:1.3.dfsg-3.1ubuntu2.2"],"ecosystem_specific":{"binaries":[{"binary_version":"1:1.3.dfsg-3.1ubuntu2.3","binary_name":"lib32z1"},{"binary_name":"lib64z1","binary_version":"1:1.3.dfsg-3.1ubuntu2.3"},{"binary_name":"libminizip1t64","binary_version":"1:1.3.dfsg-3.1ubuntu2.3"},{"binary_name":"libx32z1","binary_version":"1:1.3.dfsg-3.1ubuntu2.3"},{"binary_name":"minizip","binary_version":"1:1.3.dfsg-3.1ubuntu2.3"},{"binary_name":"zlib1g","binary_version":"1:1.3.dfsg-3.1ubuntu2.3"}],"availability":"No subscription required"},"database_specific":{"cves_map":{"cves":[{"id":"CVE-2026-85091","severity":[{"score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H","type":"CVSS_V3"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N"},{"score":"medium","type":"Ubuntu"}]}],"ecosystem":"Ubuntu:24.04:LTS"},"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8954-1.json"}},{"package":{"name":"zlib","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/zlib?arch=source&distro=stonking"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:1.3.dfsg+really1.3.2-3ubuntu1.1"}]}],"versions":["1:1.3.dfsg+really1.3.1-1ubuntu3","1:1.3.dfsg+really1.3.2-3ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"lib32z1","binary_version":"1:1.3.dfsg+really1.3.2-3ubuntu1.1"},{"binary_version":"1:1.3.dfsg+really1.3.2-3ubuntu1.1","binary_name":"lib64z1"},{"binary_version":"1:1.3.dfsg+really1.3.2-3ubuntu1.1","binary_name":"libminizip1t64"},{"binary_name":"libx32z1","binary_version":"1:1.3.dfsg+really1.3.2-3ubuntu1.1"},{"binary_version":"1:1.3.dfsg+really1.3.2-3ubuntu1.1","binary_name":"minizip"},{"binary_version":"1:1.3.dfsg+really1.3.2-3ubuntu1.1","binary_name":"zlib1g"}],"availability":"No subscription required"},"database_specific":{"cves_map":{"ecosystem":"Ubuntu:26.10","cves":[{"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-85091"}]},"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8954-1.json"}},{"package":{"name":"zlib","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/zlib?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:1.3.dfsg+really1.3.1-1ubuntu3.2"}]}],"versions":["1:1.3.dfsg+really1.3.1-1ubuntu2","1:1.3.dfsg+really1.3.1-1ubuntu3","1:1.3.dfsg+really1.3.1-1ubuntu3.1"],"ecosystem_specific":{"binaries":[{"binary_version":"1:1.3.dfsg+really1.3.1-1ubuntu3.2","binary_name":"lib32z1"},{"binary_version":"1:1.3.dfsg+really1.3.1-1ubuntu3.2","binary_name":"lib64z1"},{"binary_version":"1:1.3.dfsg+really1.3.1-1ubuntu3.2","binary_name":"libminizip1t64"},{"binary_name":"libx32z1","binary_version":"1:1.3.dfsg+really1.3.1-1ubuntu3.2"},{"binary_version":"1:1.3.dfsg+really1.3.1-1ubuntu3.2","binary_name":"minizip"},{"binary_name":"zlib1g","binary_version":"1:1.3.dfsg+really1.3.1-1ubuntu3.2"}],"availability":"No subscription required"},"database_specific":{"cves_map":{"ecosystem":"Ubuntu:26.04:LTS","cves":[{"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-85091"}]},"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8954-1.json"}}],"schema_version":"1.9.0"}