An isync security update has been released for Arch Linux.

ASA-202106-27: isync: arbitrary code execution

Arch Linux Security Advisory ASA-202106-27
=========================================
Severity: Medium
Date : 2021-06-09
CVE-ID : CVE-2021-3578
Package : isync
Type : arbitrary code execution
Remote : Yes
Link :   https://security.archlinux.org/AVG-2042

Summary
======
The package isync before version 1.4.2-1 is vulnerable to arbitrary
code execution.

Resolution
=========
Upgrade to 1.4.2-1.

# pacman -Syu "isync>=1.4.2-1"

The problem has been fixed upstream in version 1.4.2.

Workaround
=========
None.

Description
==========
A security issue was found in mbsync before version 1.4.2, where an
unchecked pointer cast allows a malicious or compromised server to
write an arbitrary integer value past the end of a heap-allocated
structure by issuing an unexpected APPENDUID response. This could be
plausibly exploited for remote code execution on the client.

Impact
=====
A remote server could cause arbitrary code execution on the mbsync
client using a crafted APPENDUID response.

References
=========
  https://sourceforge.net/p/isync/mailman/message/37297759/
  https://sourceforge.net/p/isync/isync/ci/589d2ed4283130108df5495b5510d822282e1300/
  https://security.archlinux.org/CVE-2021-3578