Browser data exfiltration via unfiltered SVG CSS
Published Apr 17, 2026 · Updated Apr 17, 2026
CSS injection in rhukster DOMSanitizer before 1.0.10 allows remote attackers to trigger browser requests through sanitized SVG. DOMSanitizer::sanitize() permits SVG style elements but checks only element attributes, leaving their text-node url() and @import directives unfiltered. Exploitation requires an application to sanitize attacker-controlled SVG and render the result in a browser, enabling page-URL disclosure and, on some browsers, cookie or session-token disclosure.
Summary
What happened
CSS injection in rhukster DOMSanitizer before 1.0.10 allows remote attackers to trigger browser requests through sanitized SVG. DOMSanitizer::sanitize() permits SVG style elements but checks only element attributes, leaving their text-node url() and @import directives unfiltered. Exploitation requires an application to sanitize attacker-controlled SVG and render the result in a browser, enabling page-URL disclosure and, on some browsers, cookie or session-token disclosure.
The record
- CVE
- CVE-2026-40301
- Published
- Apr 17, 2026
- Updated
- Apr 17, 2026
- Vendor
- rhukster
- Product
- DOMSanitizer
- Classifications
- CWE-79
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 17, 2026CVE publishedPublication date reported by the CVE source.
- Apr 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=< 1.0.10
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
- GitHub advisory SVG CSS injection proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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