{"id":"UBUNTU-CVE-2026-53727","details":"css_parser is a Ruby CSS parser. From 2.2.0 until 3.0.0, CssParser::Parser#read_remote_file in lib/css_parser/parser.rb, and therefore load_uri! and the @import-following branch of add_block!, issued HTTP and HTTPS requests against any host, port, and URI without a scheme allowlist, host or IP filtering, or protection against link-local, loopback, or RFC-1918 addresses. Location: redirects were followed recursively back into the same function, which also serviced file:// URIs, so a single attacker-controlled HTTP redirect could upgrade the bug from SSRF to arbitrary local file disclosure. Any consumer of css_parser that hands it attacker-influenced CSS together with a base_uri: option is exposed. This issue is fixed in version 3.0.0.","modified":"2026-08-20T10:45:58.906080757Z","published":"2026-07-17T21:17:00Z","upstream":["CVE-2026-53727"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-53727"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-53727"},{"type":"REPORT","url":"https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855h"}],"affected":[{"package":{"name":"ruby-css-parser","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/ruby-css-parser?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.6-1"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-css-parser","binary_version":"1.3.6-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53727.json"}},{"package":{"name":"ruby-css-parser","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/ruby-css-parser?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.6-1","1.6.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-css-parser","binary_version":"1.6.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53727.json"}},{"package":{"name":"ruby-css-parser","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/ruby-css-parser?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-css-parser","binary_version":"1.6.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53727.json"}},{"package":{"name":"ruby-css-parser","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/ruby-css-parser?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6.0-1","1.6.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-css-parser","binary_version":"1.6.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53727.json"}},{"package":{"name":"ruby-css-parser","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/ruby-css-parser?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6.0-2","1.16.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-css-parser","binary_version":"1.16.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53727.json"}},{"package":{"name":"ruby-css-parser","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/ruby-css-parser?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.19.0-1","1.21.1-1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.21.1-1","binary_name":"ruby-css-parser"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53727.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N"},{"type":"Ubuntu","score":"medium"}]}