{"id":"CVE-2026-53727","summary":"css_parser: SSRF and Local File Disclosure in `CssParser::Parser#read_remote_file`","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.","aliases":["GHSA-9pmc-p236-855h"],"modified":"2026-08-20T03:54:27.165515396Z","published":"2026-07-17T20:30:37.291Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53727.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-918"]},"references":[{"type":"WEB","url":"https://github.com/premailer/css_parser/releases/tag/v3.0.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53727.json"},{"type":"ADVISORY","url":"https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855h"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53727"},{"type":"FIX","url":"https://github.com/premailer/css_parser/commit/7d2ddf0189cd54b54f378f59daefa10cb036e476"},{"type":"FIX","url":"https://github.com/premailer/css_parser/commit/e0a151458b2a801ae265ba420862ef8b1127b3ae"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/premailer/css_parser","events":[{"introduced":"cee10f16b11dd175f17b0e5f6aefa488378e964b"},{"fixed":"7d2ddf0189cd54b54f378f59daefa10cb036e476"},{"fixed":"e0a151458b2a801ae265ba420862ef8b1127b3ae"},{"fixed":"f02be347d3a49d56ef706f5bf68621f20e3a7d40"}],"database_specific":{"cpe":"cpe:2.3:a:premailer:css_parser:2.2.0:*:*:*:*:ruby:*:*","extracted_events":[{"introduced":"2.2.0"},{"last_affected":"2.2.0"}],"source":["CPE_STRING","REFERENCES"]}}],"versions":["2.2.0","v2.2.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/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"}]}