{"schemaVersion":3,"id":"USN-8268-1","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"dnsmasq vulnerabilities\n\nAndrew S. Fasano, Royce M, and Hugo Martinez Ray discovered that Dnsmasq\ndid not allocate the necessary space to store domain names in some\ncontexts. An attacker could possibly use this issue to write\nout-of-bounds, and could cause a denial of service or execute arbitrary\ncode. (CVE-2026-2291)\n\nRoyce M discovered that Dnsmasq could loop infinitely due to erroneously\nmissing the window header. An attacker could possibly use this issue to\ncause a denial of service. This issue only affected Ubuntu 16.04 LTS,\nUbuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS,\nUbuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-4890)\n\nRoyce M discovered that a maliciously crafted packet could cause Dnsmasq\nto report a negative length. An attacker could possibly use this issue\nto cause a denial of service. This issue only affected Ubuntu 16.04 LTS,\nUbuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS,\nUbuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-4891)\n\nRoyce M and Asim Viladi Oglu Manizada discovered that certain\nconfigurations of Dnsmasq could write over the DHCPv6 CLID buffer within\na privileged helper. An attacker could possibly use this issue to cause\na denial of service or execute arbitrary code. (CVE-2026-4892)\n\nRoyce M discovered that certain configurations of Dnsmasq could bypass\ninternal bounds checks. An attacker could possibly use this issue to\npermit malformed packets, and could cause a denial of service.\n(CVE-2026-4893)\n\nHugo Martinez discovered that Dnsmasq did not check the rdlen element of\na record. An attacker could possibly use this issue to cause a denial of\nservice. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS,\nUbuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 25.10, and\nUbuntu 26.04 LTS. (CVE-2026-5172)","dates":{"published":"2026-05-12T09:23:25.000Z","modified":"2026-06-30T18:16:01.282Z","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":"dnsmasq","name":"dnsmasq","label":"dnsmasq","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/dnsmasq","purlType":"deb","versions":[{"text":"< 2.68-1ubuntu0.2+esm5","noFixRecorded":false,"fixedIn":null},{"text":"< 2.90-0ubuntu0.16.04.1+esm3","noFixRecorded":false,"fixedIn":null},{"text":"< 2.90-0ubuntu0.18.04.1+esm3","noFixRecorded":false,"fixedIn":null},{"text":"< 2.90-0ubuntu0.20.04.1+esm2","noFixRecorded":false,"fixedIn":null},{"text":"< 2.90-0ubuntu0.22.04.3","noFixRecorded":false,"fixedIn":null},{"text":"< 2.90-2ubuntu0.3","noFixRecorded":false,"fixedIn":null},{"text":"< 2.91-1ubuntu0.2","noFixRecorded":false,"fixedIn":null},{"text":"< 2.92-1ubuntu0.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 2.68-1ubuntu0.2+esm5 | < 2.90-0ubuntu0.16.04.1+esm3 | < 2.90-0ubuntu0.18.04.1+esm3 | < 2.90-0ubuntu0.20.04.1+esm2 | < 2.90-0ubuntu0.22.04.3 | < 2.90-2ubuntu0.3 | < 2.91-1ubuntu0.2 | < 2.92-1ubuntu0.2","eol":null,"hubHref":null}],"affectedCount":1,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://ubuntu.com/security/notices/USN-8268-1","label":"ubuntu.com/security/notices/USN-8268-1","hostname":"ubuntu.com","tags":["Advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-2291","label":"ubuntu.com/security/CVE-2026-2291","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-4890","label":"ubuntu.com/security/CVE-2026-4890","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-4891","label":"ubuntu.com/security/CVE-2026-4891","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-4892","label":"ubuntu.com/security/CVE-2026-4892","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-4893","label":"ubuntu.com/security/CVE-2026-4893","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-5172","label":"ubuntu.com/security/CVE-2026-5172","hostname":"ubuntu.com","tags":["REPORT"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":["CVE-2026-2291","CVE-2026-4890","CVE-2026-4891","CVE-2026-4892","CVE-2026-4893","CVE-2026-5172"]},"timeline":[{"kind":"published","date":"2026-05-12T09:23:25.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-06-30T18:16:01.282Z","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":"2026-10-20T12:00:40.042Z","stale":false,"partial":false}}