{"id":"CVE-2026-126207","summary":"Loofah: CSS url() sanitization bypass via escaped parentheses","details":"Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. Prior to 2.25.3, Loofah::HTML5::Scrub.scrub_css checks only the first parse of a style attribute, then rebuilds CSS with identifier escapes decoded so escaped parentheses, property names, comments, or quotes can become a live url() without a second safety check. An attacker can use list-style to make a viewer's browser request an attacker-chosen URL when content renders, or cursor to make the request on hover. The request can disclose the viewer's IP address, user agent, access timing, and access to internal-network hosts, but no script survives sanitization and the attacker cannot read the response. This issue is fixed in version 2.25.3.","aliases":["GHSA-m3x9-938q-5767"],"modified":"2026-11-13T10:45:57.367556273Z","published":"2026-11-12T20:53:55.553Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-180","CWE-184"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126207.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126207.json"},{"type":"FIX","url":"https://github.com/flavorjones/loofah/commit/b198a36e44c9c5408163ac50787825e8ca0b166b"},{"type":"FIX","url":"https://github.com/flavorjones/loofah/pull/324"},{"type":"WEB","url":"https://github.com/flavorjones/loofah/releases/tag/v2.25.3"},{"type":"ADVISORY","url":"https://github.com/flavorjones/loofah/security/advisories/GHSA-m3x9-938q-5767"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-126207"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/flavorjones/loofah","events":[{"introduced":"0"},{"fixed":"bbe007e52e8aeaa520b3e515235d467f5b1416e6"},{"fixed":"b198a36e44c9c5408163ac50787825e8ca0b166b"}],"database_specific":{"extracted_events":[{"source":"AFFECTED_FIELD","strategy":"StringRangeExpression","range":[{"introduced":"0"},{"fixed":"2.25.3"}]},{"source":"REFERENCES_COMMIT","range":[{"fixed":"b198a36e44c9c5408163ac50787825e8ca0b166b"}]},{"range":[{"fixed":"bbe007e52e8aeaa520b3e515235d467f5b1416e6"}],"source":"REFERENCES_TAG","original_tag":"v2.25.3"}]}}],"versions":["v2.25.2","v2.25.1","v2.25.0","v2.24.1","v2.24.0","v2.23.1","v2.23.0","v2.22.0","v2.21.4","v2.21.3","v2.21.2","v2.21.1","v2.21.0","v2.21.0.rc1","v2.20.0","v2.19.0","v2.18.0","v2.17.0","v2.16.0","v2.15.0","v2.14.0","v2.13.0","v2.12.0","v2.11.0","v2.10.0","v2.9.1","v2.9.0","v2.8.0","v2.7.0","v2.6.0","v2.5.0","v2.4.0","v2.3.1","v2.3.0","v2.2.2","v2.2.1","v2.2.0","v2.1.1","v2.1.0","v2.1.0.rc2","v2.1.0.rc1","v2.0.3","v2.0.2","v2.0.1","v2.0.0","v1.2.1","v1.2.0","v1.1.0","v1.0.0","v1.0.0.beta.1","v0.4.7","v0.4.6","v0.4.5","v0.4.4","v0.4.3","v0.4.2","v0.4.1","v0.4.0","v0.3.1","v0.3.0","v0.2.2","v0.2.1","v0.2.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-126207.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N"}]}