SSRF and local file disclosure via unchecked redirects
Published Jul 17, 2026 · Updated Jul 17, 2026
SSRF in Premailer css_parser before 3.0.0 allows remote attackers to reach internal services through attacker-influenced CSS. CssParser::Parser#read_remote_file follows @import URLs and redirects without validating schemes, hosts, or resolved private addresses, and its redirect path accepts file URIs through File.read. Exposure requires a consumer to parse attacker-influenced CSS with base_uri; requests can reach internal services, while CSS-shaped local files can be disclosed.
Summary
What happened
SSRF in Premailer css_parser before 3.0.0 allows remote attackers to reach internal services through attacker-influenced CSS. CssParser::Parser#read_remote_file follows @import URLs and redirects without validating schemes, hosts, or resolved private addresses, and its redirect path accepts file URIs through File.read. Exposure requires a consumer to parse attacker-influenced CSS with base_uri; requests can reach internal services, while CSS-shaped local files can be disclosed.
The record
- CVE
- CVE-2026-53727
- Published
- Jul 17, 2026
- Updated
- Jul 17, 2026
- Vendor
- Premailer
- Product
- css_parser
- Classifications
- CWE-73, CWE-918
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 17, 2026CVE publishedPublication date reported by the CVE source.
- Jul 17, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 3.0.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- poc.rb SSRF and file-disclosure reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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