CVE-2023-42116

Name	CVE-2023-42116
Description	Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of NTLM challenge requests. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account. Was ZDI-CAN-17515.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-3599-1, DSA-5512-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
exim4 (PTS)	bullseye	4.94.2-7+deb11u2	fixed
	bullseye (security)	4.94.2-7+deb11u3	fixed
	bookworm	4.96-15+deb12u4	fixed
	bookworm (security)	4.96-15+deb12u5	fixed
	sid, trixie	4.98-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Origin
exim4	source	buster	4.92-8+deb10u8	DLA-3599-1
exim4	source	bullseye	4.94.2-7+deb11u1	DSA-5512-1
exim4	source	bookworm	4.96-15+deb12u2	DSA-5512-1
exim4	source	(unstable)	4.97~RC1-2

Notes

https://www.zerodayinitiative.com/advisories/ZDI-23-1470/
https://bugs.exim.org/show_bug.cgi?id=3000
https://git.exim.org/exim.git/log/refs/heads/exim-4.96%20security/exim.git/commit/936e342d560e218c2aee5cb2295be925c27c2106
https://www.openwall.com/lists/oss-security/2023/09/29/5
https://www.openwall.com/lists/oss-security/2023/10/01/4
https://exim.org/static/doc/security/CVE-2023-zdi.txt