Heap-based buffer overflow in Exim - CVE-2019-16928
Published: September 28, 2019 / Updated: March 8, 2022
Vulnerability identifier: #VU21399
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber
CVE-ID: CVE-2019-16928
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vendor: Exim
Affected software:
Exim
Exim
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to a boundary error within the string_vformat() function in string.c when processing an overly long argument for EHLO command. A remote non-authenticated attacker can send a very long string as an argument for the EHLO command, trigger a heap-based buffer overflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
How to mitigate CVE-2019-16928
Install the latest version from vendor's website.
Sources
- http://www.openwall.com/lists/oss-security/2019/09/28/1
- http://www.openwall.com/lists/oss-security/2019/09/28/2
- http://www.openwall.com/lists/oss-security/2019/09/28/3
- https://bugs.exim.org/show_bug.cgi?id=2449
- https://git.exim.org/exim.git/commit/478effbfd9c3cc5a627fc671d4bf94d13670d65f
- https://lists.exim.org/lurker/message/20190927.032457.c1044d4c.en.html