CVE-2026-53727

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 v3 8.6 HIGH

8.6^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 4.0

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope CHANGED

References

Link	Resource
https://github.com/premailer/css_parser/commit/7d2ddf0189cd54b54f378f59daefa10cb036e476	Patch
https://github.com/premailer/css_parser/commit/e0a151458b2a801ae265ba420862ef8b1127b3ae	Patch
https://github.com/premailer/css_parser/releases/tag/v3.0.0	Product
https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855h	Exploit Mitigation Vendor Advisory
https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855h	Exploit Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:premailer:css_parser:2.2.0:*:*:*:*:ruby:*:*

History

No history.

Information

Published : 2026-07-17 21:17

Updated : 2026-08-18 15:33

NVD link : CVE-2026-53727

Mitre link : CVE-2026-53727

CVE.ORG link : CVE-2026-53727

JSON object : View

Products Affected

premailer

css_parser

CWE

CWE-918

Server-Side Request Forgery (SSRF)

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