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Exploited. On CISA's list since 2023-06-22.
CVE-2020-35730 · Roundcube Roundcube Webmail · Published 2020-12-28
6.1 out of 10
CVSS rates it medium.
33%
Estimated chance of exploitation in the next 30 days, higher than 98% of all scored flaws (EPSS, 2026-10-29).
Yes
CISA has seen it exploited in real attacks. For US government agencies the fix is deadline passed 1205 days ago (2023-07-13).
Apply updates per vendor instructions.
Roundcube Webmail contains a cross-site scripting (XSS) vulnerability that allows an attacker to send a plain text e-mail message with Javascript in a link reference element that is mishandled by linkref_addinindex in rcube_string_replacer.php.
An XSS issue was discovered in Roundcube Webmail before 1.2.13, 1.3.x before 1.3.16, and 1.4.x before 1.4.10. The attacker can send a plain text e-mail message, with JavaScript in a link reference element that is mishandled by linkref_addindex in rcube_string_replacer.php.
From the NVD.
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Untrusted content becomes code running in another visitor's browser.
CWE-79 · CISA KEV; NVD record: 134c704f-9b21-4f2e-91b3-4a467353bcc0; NVD record: nvd@nist.gov
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