Fetchmail Security and Errata Information
These security issues (listed immediately below) and critical
issues have become
known to the fetchmail maintainer to the date mentioned above.
Note that fetchmail 6.3.X and older are no longer supported and contain
some of the problems mentioned below, even if they aren't mentioned
in the security announcements:
Fetchmail would fail to negotiate a TLS encrypted session in some circumstances, continuing a clear-text connection.
Fetchmail could log possibly
sensitive data or garbage, or crash, when logging information longer
than 2 kB, on some systems.
Fetchmail could crash and
possibly reveal fragments of confidential data during
Fetchmail was vulnerable
to chosen-plaintext attacks against cipher block
chaining initialization vectors because it disabled an
OpenSSL countermeasure against this attack.
Fetchmail could hang for
indefinite amounts of time during STARTTLS negotiations,
causing mail fetches to stall. This was a long-standing bug
fixed in release 6.3.20.
- EN-2010-03: Fetchmail fails
POP3/IMAP authentication by not performing SASL AUTH
properly. This was a long-standing bug fixed in release
Fetchmail could exhaust all
available memory and abort on certain computers (for
instance Linux) in multibyte locales (for instance UTF-8)
when dumping malformed headers in debug (-v -v) mode.
This bug was introduced long before 6.0.0 and has been fixed in
- CVE-2010-0562: Fetchmail would overrun the heap when displaying X.509 TLS/SSL certificates with characters with high bit set in verbose mode on platforms where char is a signed type. This bug was introduced in release 6.3.11 and has been fixed in release 6.3.14.
- CVE-2009-2666: Fetchmail was found to validate SSL/TLS X.509 certificates improperly and allow man-in-the-middle-attacks to go undetected. This bug has been fixed in release 6.3.11. For previous versions, use the patch contained in the security announcement.
- CVE-2008-2711: Fetchmail can crash in verbose mode when logging long message headers. This bug has been fixed in release 6.3.9. For 6.3.8, use the patch contained in the security announcement.
- CVE-2007-4565: Fetchmail can crash when the SMTP server refuses a warning message generated by fetchmail. This bug was introduced in fetchmail 4.6.8 and has been fixed in release 6.3.9. For 6.3.8, use the patch contained in this security announcement.
- CVE-2007-1558: Fetchmail's APOP client was found to validate APOP challenges insufficiently, making man-in-the-middle attacks on APOP secrets unnecessarily easier than need be. This bug was long-standing, fetchmail 6.3.8 and newer validate the APOP challenge more strictly.
- CVE-2006-5974: Fetchmail was found to crash when refusing a message that was bound to be delivered by an MDA. This bug was introduced into fetchmail 6.3.5 and fixed in 6.3.6.
- CVE-2006-5867: Fetchmail was found to omit TLS or send the password in clear text despite the configuration stating otherwise. This was a long-standing bug reported by Isaac Wilcox, fixed in fetchmail 6.3.6. There will be no 6.2.X releases to fix this bug in 6.2.X.
- CVE-2006-0321: Fetchmail was found to crash after bouncing a message with bad addresses. This bug was introduced with fetchmail 6.3.0 and fixed in fetchmail 6.3.2.
- CVE-2005-4348: Fetchmail was found to contain a bug (null pointer dereference) that can be exploited to a denial of service attack when fetchmail runs in multidrop mode. 126.96.36.199 and 6.3.1 have this bug fixed.
- CVE-2005-3088: Fetchmailconf was found to open the configuration files world-readable, writing data to them, and only then tightening up permissions, which may cause password information to be visible to other users. This bug affected fetchmail 6.2.0, 6.2.5 and 188.8.131.52. The bug is fixed in fetchmail 184.108.40.206 and 6.3.0.
- CVE-2005-2335: Fetchmail was found to contain a remotely exploitable code injection vulnerability (potentially privileged code) in the POP3 code, affecting both the 6.2.0 and 6.2.5 releases. 220.127.116.11, 18.104.22.168 and 6.3.0 have got this bug fixed. (Other versions have not been checked if they contain this bug.)
to the newest fetchmail version.