Remote content-blocking bypass via unclosed SVG url()
Published Aug 17, 2026 · Updated Aug 18, 2026
Remote content-blocking bypass in Roundcube Webmail before 1.6.18 and 1.7.3 allows attackers to trigger external URL loads via SVG content. In rcube_washtml.php, wash_attribs() accepts FuncIRI values that start with url( even when the closing parenthesis is missing, then passes the extracted URL through wash_uri() and rebuilds the attribute as if it were safe. Reachability depends on a victim rendering attacker-supplied SVG mail content; the resulting fetch can disclose client access patterns and, in some deployments, assist session-level privilege abuse.
Summary
What happened
Remote content-blocking bypass in Roundcube Webmail before 1.6.18 and 1.7.3 allows attackers to trigger external URL loads via SVG content. In rcube_washtml.php, wash_attribs() accepts FuncIRI values that start with url( even when the closing parenthesis is missing, then passes the extracted URL through wash_uri() and rebuilds the attribute as if it were safe. Reachability depends on a victim rendering attacker-supplied SVG mail content; the resulting fetch can disclose client access patterns and, in some deployments, assist session-level privilege abuse.
The record
- CVE
- CVE-2026-75003
- Published
- Aug 17, 2026
- Updated
- Aug 18, 2026
- Vendor
- Roundcube
- Product
- Roundcube Webmail
- Classifications
- CWE-669
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 17, 2026CVE publishedPublication date reported by the CVE source.
- Aug 18, 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=1.6.0 <1.6.18
- Affected versionversion=1.7.0 <1.7.3
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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