An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. imap/command.c mishandles a NO response without a message.

An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. imap/message.c has a stack-based buffer overflow for a FETCH response with a long INTERNALDATE field.

An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. imap/command.c mishandles a long IMAP status mailbox literal count size.

An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. imap_quote_string in imap/util.c does not leave room for quote characters, leading to a stack-based buffer overflow.

An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. imap_quote_string in imap/util.c has an integer underflow.

An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. They allow remote IMAP servers to execute arbitrary commands via backquote characters, related to the mailboxes command associated with a manual subscription or unsubscription.

An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. imap/util.c mishandles ".." directory traversal in a mailbox name.

An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. pop.c mishandles a zero-length UID.

An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. They allow remote IMAP servers to execute arbitrary commands via backquote characters, related to the mailboxes command associated with an automatic subscription.

An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. imap/message.c has a stack-based buffer overflow for a FETCH response with a long RFC822.SIZE field.

An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. They have a buffer overflow via base64 data.

An issue was discovered in NeoMutt before 2018-07-16. nntp_add_group in newsrc.c has a stack-based buffer overflow because of incorrect sscanf usage.

An issue was discovered in NeoMutt before 2018-07-16. nntp.c proceeds even if memory allocation fails for messages data.

An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. pop.c does not forbid characters that may have unsafe interaction with message-cache pathnames, as demonstrated by a '/' character.

An issue was discovered in NeoMutt before 2018-07-16. newsrc.c does not properly restrict '/' characters that may have unsafe interaction with cache pathnames.

Mutt before 1.14.4 and NeoMutt before 2020-06-19 have a STARTTLS buffering issue that affects IMAP, SMTP, and POP3. When a server sends a "begin TLS" response, the client reads additional data (e.g., from a man-in-the-middle attacker) and evaluates it in a TLS context, aka "response injection."

Mutt before 2.0.2 and NeoMutt before 2020-11-20 did not ensure that $ssl_force_tls was processed if an IMAP server's initial server response was invalid. The connection was not properly closed, and the code could continue attempting to authenticate. This could result in authentication credentials being exposed on an unencrypted connection, or to a machine-in-the-middle.

Mutt 1.11.0 through 2.0.x before 2.0.7 (and NeoMutt 2019-10-25 through 2021-05-04) has a $imap_qresync issue in which imap/util.c has an out-of-bounds read in situations where an IMAP sequence set ends with a comma. NOTE: the $imap_qresync setting for QRESYNC is not enabled by default.

In neomutt and mutt, the To and Cc email headers are not validated by cryptographic signing which allows an attacker that intercepts a message to change their value and include himself as a one of the recipients to compromise message confidentiality.

In mutt and neomutt the In-Reply-To email header field is not protected by cryptographic signing which allows an attacker to reuse an unencrypted but signed email message to impersonate the original sender.

In mutt and neomutt, PGP encryption does not use the --hidden-recipient mode which may leak the Bcc email header field by inferring from the recipients info.