In the rcfilters plugin 2.1.6 for Roundcube, XSS exists via the _whatfilter and _messages parameters (in the Filters section of the settings).
https://github.com/roundcube/roundcubemail/issues/6437
https://github.com/eagle00789/RC_Filters/issues/19
https://www.exploit-db.com/exploits/45437/
Source: Mitre, NVD
Published: 2018-09-09
Updated: 2026-06-17
Base Score: 3.5
Vector: CVSS2#AV:N/AC:M/Au:S/C:N/I:P/A:N
Severity: Low
Base Score: 5.4
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Severity: Medium
EPSS: 0.00319