{"schemaVersion":3,"id":"USN-8486-1","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"libssh2 vulnerabilities\n\nIt was discovered that libssh2 incorrectly handled the sftp_symlink()\nfunction. A malicious SSH server or machine-in-the-middle attacker could\npossibly use this issue to obtain sensitive information or cause a denial\nof service. (CVE-2025-15661)\n\nIt was discovered that libssh2 had a pre-authentication denial of service\nvulnerability in the SSH_MSG_EXT_INFO handler. A malicious SSH server could\npossibly use this issue to cause a client CPU exhaustion loop, resulting in\na denial of service. (CVE-2026-55199)\n\nIt was discovered that libssh2 incorrectly handled packet length fields. A\nremote attacker could possibly use this issue to execute arbitrary code.\nThis issue only affected Ubuntu 25.10 and Ubuntu 26.04 LTS.\n(CVE-2026-55200)","dates":{"published":"2026-06-30T12:41:51.000Z","modified":"2026-07-01T23:32:46.286Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":null,"severity":"unknown","version":null,"versionLabel":null,"source":null,"vector":null,"computed":false,"selection":"none"},"metrics":[]},"epss":{"probability":null,"percentile":null,"severity":"unknown","asOf":null,"change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[],"last30":[]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[],"affected":[{"vendor":"ubuntu","product":"libssh2","name":"libssh2","label":"libssh2","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/libssh2","purlType":"deb","versions":[{"text":"< 1.11.0-4.1ubuntu0.24.04.2","noFixRecorded":false,"fixedIn":null},{"text":"< 1.11.1-1ubuntu0.25.10.2","noFixRecorded":false,"fixedIn":null},{"text":"< 1.11.1-1ubuntu0.26.04.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.11.0-4.1ubuntu0.24.04.2 | < 1.11.1-1ubuntu0.25.10.2 | < 1.11.1-1ubuntu0.26.04.2","eol":null,"hubHref":null}],"affectedCount":1,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://ubuntu.com/security/notices/USN-8486-1","label":"ubuntu.com/security/notices/USN-8486-1","hostname":"ubuntu.com","tags":["Advisory"]},{"url":"https://ubuntu.com/security/CVE-2025-15661","label":"ubuntu.com/security/CVE-2025-15661","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-55199","label":"ubuntu.com/security/CVE-2026-55199","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-55200","label":"ubuntu.com/security/CVE-2026-55200","hostname":"ubuntu.com","tags":["REPORT"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":["CVE-2025-15661","CVE-2026-55199","CVE-2026-55200"]},"timeline":[{"kind":"published","date":"2026-06-30T12:41:51.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-07-01T23:32:46.286Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":0,"level":"minimal","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-20T19:58:15.836Z","stale":false,"partial":false}}