The IMAP Client for Sylpheed 0.8.11 allows remote malicious IMAP servers to cause a denial of service (crash) via certain large literal size values that cause either integer signedness errors or integer overflow errors.

Format string vulnerability in send_message.c for Sylpheed-claws 0.9.4 through 0.9.6 allows remote SMTP servers to cause a denial of service (crash) in sylpheed via format strings in an error message.

Buffer overflow in Sylpheed before 1.0.3 and other versions before 1.9.5 allows remote attackers to execute arbitrary code via an e-mail message with certain headers containing non-ASCII characters that are not properly handled when the user replies to the message.

Buffer overflow in Sylpheed before 1.0.4 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via attachments with MIME-encoded file names.

Stack-based buffer overflow in the ldif_get_line function in ldif.c of Sylpheed before 2.1.6 allows user-assisted attackers to execute arbitrary code by having local users import LDIF files with long lines.

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.

Sylpheed 2.2.7 and earlier does not properly use the --status-fd argument when invoking GnuPG, which prevents Sylpheed from visually distinguishing between signed and unsigned portions of OpenPGP messages with multiple components, which allows remote attackers to forge the contents of a message without detection.

Format string vulnerability in the inc_put_error function in src/inc.c in Sylpheed 2.4.4, and Sylpheed-Claws (Claws Mail) 1.9.100 and 2.10.0, allows remote POP3 servers to execute arbitrary code via format string specifiers in crafted replies.