{"schemaVersion":3,"id":"CVE-2026-69186","aliases":["UBUNTU-CVE-2026-69186","DEBIAN-CVE-2026-69186"],"status":"published","duplicateOf":null,"title":null,"description":"c-ares is an asynchronous resolver library. Prior to 1.34.7, ares_dns_parse() trusts the attacker-controlled ANCOUNT, NSCOUNT, and ARCOUNT fields before confirming that the DNS response contains enough bytes for the claimed records. Because process_answer() invokes parsing before transaction ID and question validation, a malicious DNS response can cause ares_dns_record_rr_prealloc() and ares_array_set_size() to reserve disproportionate heap memory for a tiny message. Repeated responses create large allocation and release cycles that can degrade or deny name resolution, without causing memory corruption or information disclosure. This issue is fixed in version 1.34.7.","dates":{"published":"2026-09-18T17:25:42.440Z","modified":"2026-09-18T19:51:33.881Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":5.3,"severity":"medium","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":5.3,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Ubuntu","score":5.3,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","exploitability":10,"impact":2.3,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Debian","score":5.3,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","exploitability":10,"impact":2.3,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":5.3,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00524,"percentile":0.43532,"severity":"low","asOf":"2026-10-21T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-21T00:00:00.000Z","baselineScore":0.00524},"history":[{"date":"2026-09-19T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00524,"percentile":0.43532}],"last30":[{"date":"2026-09-21T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00524,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00524,"percentile":0.43532}]},"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":[{"id":"CWE-400","name":"Uncontrolled Resource Consumption","description":"The product does not properly control the allocation and maintenance of a limited resource.","type":"weakness","status":"Draft","abstraction":"Class","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/400.html"}],"affected":[{"vendor":"c-ares","product":"c-ares","name":"c-ares","label":"c-ares","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 1.34.7","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.34.7","eol":null,"hubHref":"/vendor/c-ares/c-ares"},{"vendor":"debian","product":"c-ares","name":"c-ares","label":"c-ares","ecosystem":"Debian","cpePart":null,"purl":"pkg:deb/debian/c-ares","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null},{"text":"< 1.34.7-1","noFixRecorded":false,"fixedIn":null}],"versionsText":"All versions (No fix recorded) | < 1.34.7-1","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"c-ares","name":"c-ares","label":"c-ares","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/c-ares","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null},{"text":"< 1.27.0-1.0ubuntu1.1","noFixRecorded":false,"fixedIn":null},{"text":"< 1.34.6-1ubuntu0.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"All versions (No fix recorded) | < 1.27.0-1.0ubuntu1.1 | < 1.34.6-1ubuntu0.2","eol":null,"hubHref":null}],"affectedCount":3,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/c-ares/c-ares/security/advisories/GHSA-jv8r-gqr9-68wj","label":"github.com/c-ares/c-ares/security/advisories/GHSA-jv8r-gqr9-68wj","hostname":"github.com","tags":["X Refsource CONFIRM","REPORT"]},{"url":"https://github.com/c-ares/c-ares/pull/1134","label":"github.com/c-ares/c-ares/pull/1134","hostname":"github.com","tags":["X Refsource MISC"]},{"url":"https://github.com/c-ares/c-ares/commit/e47c203f91cd8b749c8736bc18d75a31ffdec8f4","label":"github.com/c-ares/c-ares/commit/e47c203f91cd8b749c8736bc18d75a31ffdec8f4","hostname":"github.com","tags":["X Refsource MISC"]},{"url":"https://github.com/c-ares/c-ares/commit/eaded4cb200b2a5f8d73f11021ff7c8d6968aaab","label":"github.com/c-ares/c-ares/commit/eaded4cb200b2a5f8d73f11021ff7c8d6968aaab","hostname":"github.com","tags":["X Refsource MISC"]},{"url":"https://github.com/c-ares/c-ares/releases/tag/v1.34.7","label":"github.com/c-ares/c-ares/releases/tag/v1.34.7","hostname":"github.com","tags":["X Refsource MISC"]},{"url":"https://ubuntu.com/security/CVE-2026-69186","label":"ubuntu.com/security/CVE-2026-69186","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-69186","label":"www.cve.org/CVERecord?id=CVE-2026-69186","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://www.openwall.com/lists/oss-security/2026/07/06/8","label":"www.openwall.com/lists/oss-security/2026/07/06/8","hostname":"www.openwall.com","tags":["REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-69186","label":"security-tracker.debian.org/tracker/CVE-2026-69186","hostname":"security-tracker.debian.org","tags":["Advisory"]},{"url":"https://ubuntu.com/security/notices/USN-8951-1","label":"ubuntu.com/security/notices/USN-8951-1","hostname":"ubuntu.com","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":["MGASA-2026-0343","OPENSUSE-SU-2026:11593-1","OPENSUSE-SU-2026:21721-1","RHSA-2026:40574","SUSE-SU-2026:23364-1","SUSE-SU-2026:23414-1","SUSE-SU-2026:23597-1","SUSE-SU-2026:4021-1"],"duplicates":[],"related":["OPENSUSE-SU-2026:11593-1","OPENSUSE-SU-2026:21721-1","SUSE-SU-2026:23364-1","SUSE-SU-2026:23414-1","SUSE-SU-2026:23597-1","SUSE-SU-2026:4021-1"]},"timeline":[{"kind":"published","date":"2026-09-18T17:25:42.440Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-09-18T19:51:33.881Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":21,"level":"low","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-22T00:32:38.602Z","stale":false,"partial":false}}