Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Premailer | Css Parser | 2.2.0 |
Related Weaknesses (CWE)
References
- https://github.com/premailer/css_parser/commit/7d2ddf0189cd54b54f378f59daefa10cbPatch
- https://github.com/premailer/css_parser/commit/e0a151458b2a801ae265ba420862ef8b1Patch
- https://github.com/premailer/css_parser/releases/tag/v3.0.0Product
- https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855hExploitMitigationVendor Advisory
- https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855hExploitMitigationVendor Advisory
FAQ
What is CVE-2026-53727?
CVE-2026-53727 is a vulnerability with a CVSS score of 8.6 (HIGH). 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 ...
How severe is CVE-2026-53727?
CVE-2026-53727 has been rated HIGH with a CVSS base score of 8.6/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-53727?
Check the references section above for vendor advisories and patch information. Affected products include: Premailer Css Parser.