Sylpheed-Claws before 2.2.2 and Sylpheed before 2.2.6 allow remote attackers to bypass the URI check functionality and makes it easier to conduct phishing attacks via a URI that begins with a space character.
Exploitability
AV:NAC:HAu:NImpact
C:NI:PA:N2.6/AV:N/AC:H/Au:N/C:N/I:P/A:N