A flaw was found in mbsync in isync 1.4.0 through 1.4.3. Due to an unchecked condition, a malicious or compromised IMAP server could use a crafted mail message that lacks headers (i.e., one that starts with an empty line) to provoke a heap overflow, which could conceivably be exploited for remote code execution.
www.openwall.com/lists/oss-security/2021/12/03/2
bugs.debian.org/cgi-bin/bugreport.cgi?bug=999804
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CYZ2GNB4ZO2T27D2XNUWMCS3THZYSJQU/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LCBSY7OZ57XNC6ZYXF6WU5KBSWITZVDX/
security.gentoo.org/glsa/202208-15
sourceforge.net/p/isync/isync/commit_browser
sourceforge.net/p/isync/isync/ref/master/tags/