{"id":"UBUNTU-CVE-2026-9547","details":"When a libcurl-based application performs transfers via `SCP://` or `SFTP://` and utilizes the `CURLOPT_SSH_KEYFUNCTION` callback, it may silently accept an untrusted server. This vulnerability occurs when a server presents a host key type that does not match the specific key type already recorded for that host in the `known_hosts` file. Instead of rejecting the mismatch, the callback mechanism fails to properly enforce the restriction, allowing the connection to succeed without warning and risking a potential man-in-the-middle attack.","modified":"2026-07-08T09:45:46.438594894Z","published":"2026-06-24T14:00:00Z","related":["USN-8487-1"],"upstream":["CVE-2026-9547"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-9547"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-9547"},{"type":"REPORT","url":"https://curl.se/L7HzKXisfJ/CVE-2026-9547.md"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8487-1"}],"affected":[{"package":{"name":"curl","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/curl?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.81.0-1ubuntu1.25"}]}],"versions":["7.74.0-1.3ubuntu2","7.74.0-1.3ubuntu3","7.80.0-3","7.81.0-1","7.81.0-1ubuntu1.1","7.81.0-1ubuntu1.2","7.81.0-1ubuntu1.3","7.81.0-1ubuntu1.4","7.81.0-1ubuntu1.6","7.81.0-1ubuntu1.7","7.81.0-1ubuntu1.8","7.81.0-1ubuntu1.10","7.81.0-1ubuntu1.11","7.81.0-1ubuntu1.13","7.81.0-1ubuntu1.14","7.81.0-1ubuntu1.15","7.81.0-1ubuntu1.16","7.81.0-1ubuntu1.17","7.81.0-1ubuntu1.18","7.81.0-1ubuntu1.19","7.81.0-1ubuntu1.20","7.81.0-1ubuntu1.21","7.81.0-1ubuntu1.22","7.81.0-1ubuntu1.23","7.81.0-1ubuntu1.24"],"ecosystem_specific":{"binaries":[{"binary_name":"curl","binary_version":"7.81.0-1ubuntu1.25"},{"binary_name":"libcurl3-gnutls","binary_version":"7.81.0-1ubuntu1.25"},{"binary_name":"libcurl3-nss","binary_version":"7.81.0-1ubuntu1.25"},{"binary_version":"7.81.0-1ubuntu1.25","binary_name":"libcurl4"}],"availability":"No subscription required","priority_reason":"Upstream defined this as low severity"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9547.json"}},{"package":{"name":"curl","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/curl?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.5.0-2ubuntu10.10"}]}],"versions":["8.2.1-1ubuntu3","8.2.1-1ubuntu3.1","8.4.0-2ubuntu1","8.5.0-2ubuntu1","8.5.0-2ubuntu2","8.5.0-2ubuntu8","8.5.0-2ubuntu9","8.5.0-2ubuntu10","8.5.0-2ubuntu10.1","8.5.0-2ubuntu10.2","8.5.0-2ubuntu10.3","8.5.0-2ubuntu10.4","8.5.0-2ubuntu10.5","8.5.0-2ubuntu10.6","8.5.0-2ubuntu10.7","8.5.0-2ubuntu10.8","8.5.0-2ubuntu10.9"],"ecosystem_specific":{"binaries":[{"binary_name":"curl","binary_version":"8.5.0-2ubuntu10.10"},{"binary_version":"8.5.0-2ubuntu10.10","binary_name":"libcurl3t64-gnutls"},{"binary_name":"libcurl4t64","binary_version":"8.5.0-2ubuntu10.10"}],"availability":"No subscription required","priority_reason":"Upstream defined this as low severity"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9547.json"}},{"package":{"name":"curl","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/curl?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.14.1-2ubuntu1.4"}]}],"versions":["8.12.1-3ubuntu1","8.13.0-5ubuntu1","8.14.1-1ubuntu2","8.14.1-1ubuntu3","8.14.1-2ubuntu1","8.14.1-2ubuntu1.1","8.14.1-2ubuntu1.2","8.14.1-2ubuntu1.3"],"ecosystem_specific":{"priority_reason":"Upstream defined this as low severity","binaries":[{"binary_version":"8.14.1-2ubuntu1.4","binary_name":"curl"},{"binary_version":"8.14.1-2ubuntu1.4","binary_name":"libcurl3t64-gnutls"},{"binary_version":"8.14.1-2ubuntu1.4","binary_name":"libcurl4t64"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9547.json"}},{"package":{"name":"curl","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/curl?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.18.0-1ubuntu2.2"}]}],"versions":["8.14.1-2ubuntu1","8.17.0-1ubuntu1","8.18.0-1ubuntu1","8.18.0-1ubuntu2","8.18.0-1ubuntu2.1"],"ecosystem_specific":{"binaries":[{"binary_name":"curl","binary_version":"8.18.0-1ubuntu2.2"},{"binary_name":"libcurl3t64-gnutls","binary_version":"8.18.0-1ubuntu2.2"},{"binary_name":"libcurl4t64","binary_version":"8.18.0-1ubuntu2.2"}],"availability":"No subscription required","priority_reason":"Upstream defined this as low severity"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9547.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"},{"type":"Ubuntu","score":"low"}]}