{"id":"CVE-2026-53727","state":"PUBLISHED","title":"css_parser: SSRF and Local File Disclosure in `CssParser::Parser#read_remote_file`","description":"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.","publishedAt":"2026-07-17T20:30:37.291Z","updatedAt":"2026-07-20T13:48:30.250Z","severity":{"score":8.9,"label":"High","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["premailer css_parser"],"affected":[{"vendor":"premailer","product":"css_parser","versions":[{"version":"< 3.0.0","status":"affected"}]}],"references":["https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855h","https://github.com/premailer/css_parser/commit/7d2ddf0189cd54b54f378f59daefa10cb036e476","https://github.com/premailer/css_parser/commit/e0a151458b2a801ae265ba420862ef8b1127b3ae","https://github.com/premailer/css_parser/releases/tag/v3.0.0"],"weaknesses":["CWE-918"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53727.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53727","state":"PUBLISHED","datePublished":"2026-07-17T20:30:37.291Z","dateUpdated":"2026-07-20T13:48:30.250Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-10T16:43:31.242Z"},"containers":{"cna":{"title":"css_parser: SSRF and Local File Disclosure in `CssParser::Parser#read_remote_file`","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"premailer","product":"css_parser","versions":[{"version":"< 3.0.0","status":"affected"}]}],"references":[{"url":"https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855h","name":"https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855h","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/premailer/css_parser/commit/7d2ddf0189cd54b54f378f59daefa10cb036e476","name":"https://github.com/premailer/css_parser/commit/7d2ddf0189cd54b54f378f59daefa10cb036e476","tags":["x_refsource_MISC"]},{"url":"https://github.com/premailer/css_parser/commit/e0a151458b2a801ae265ba420862ef8b1127b3ae","name":"https://github.com/premailer/css_parser/commit/e0a151458b2a801ae265ba420862ef8b1127b3ae","tags":["x_refsource_MISC"]},{"url":"https://github.com/premailer/css_parser/releases/tag/v3.0.0","name":"https://github.com/premailer/css_parser/releases/tag/v3.0.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"HIGH","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.9,"baseSeverity":"HIGH","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-918","lang":"en","description":"CWE-918: Server-Side Request Forgery (SSRF)","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-17T20:30:37.291Z"},"source":{"advisory":"GHSA-9pmc-p236-855h","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855h","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-20T13:48:25.291408Z","id":"CVE-2026-53727","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-20T13:48:30.250Z"}}]}}}