Subject: [ASA-201910-1] exim: arbitrary code execution

Arch Linux Security Advisory ASA-201910-1
=========================================

Severity: Critical
Date    : 2019-10-02
CVE-ID  : CVE-2019-16928
Package : exim
Type    : arbitrary code execution
Remote  : Yes
Link    : https://security.archlinux.org/AVG-1038

Summary
=======

The package exim before version 4.92.3-1 is vulnerable to arbitrary
code execution.

Resolution
==========

Upgrade to 4.92.3-1.

# pacman -Syu "exim>=4.92.3-1"

The problem has been fixed upstream in version 4.92.3.

Workaround
==========

None.

Description
===========

It has been discovered that Exim before 4.92.3 is vulnerable to a heap-
based buffer overflow in string_vformat (string.c) involving a long
EHLO command leading to remote code execution.

Impact
======

A remote attacker is able to execute arbitrary code on the affected
host by sending a specifically crafted long EHLO command.

References
==========

https://www.exim.org/static/doc/security/CVE-2019-16928.txt
https://bugs.exim.org/show_bug.cgi?id=2449
https://git.exim.org/exim.git/commitdiff/478effbfd9c3cc5a627fc671d4bf94d13670d65f
https://www.openwall.com/lists/oss-security/2019/09/28/1
https://security.archlinux.org/CVE-2019-16928