Actively exploited · Published Sep 27, 2019 · Assigned by mitre

CVE-2019-16928

Critical 9.8 Exploited

In plain English

A critical-severity out-of-bounds write in Exim Internet Mailer from Exim. Attackers are actively exploiting it in the wild (listed by CISA on March 3, 2022). The chance it is exploited in the next 30 days is estimated at 41.6% (higher than 99% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical

Exploit odds (30 days)41.6%top 1.3% of all CVEs

Exploited in the wildYesCISA KEV since Mar 3, 2022

Attack toolingNoneno public tooling known

CISA guidance

Apply updates per vendor instructions.

Federal agencies must remediate by Mar 17, 2022.

Official description

Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than CVE-2019-15846. There is a heap-based buffer overflow in string_vformat in string.c involving a long EHLO command.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Alpine:v3.20	exim	4.92.2-r1	ALPINE-CVE-2019-16928
Alpine:v3.21	exim	4.92.2-r1	ALPINE-CVE-2019-16928
Alpine:v3.22	exim	4.92.2-r1	ALPINE-CVE-2019-16928
Alpine:v3.23	exim	4.92.2-r1	ALPINE-CVE-2019-16928
Alpine:v3.24	exim	4.92.2-r1	ALPINE-CVE-2019-16928
Debian:12	exim4	4.92.2-3	DEBIAN-CVE-2019-16928
Debian:13	exim4	4.92.2-3	DEBIAN-CVE-2019-16928
Debian:14	exim4	4.92.2-3	DEBIAN-CVE-2019-16928

Affected products (as reported)

Vendor	Product	Versions
n/a	n/a	n/a

Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

https://lists.exim.org/lurker/message/20190927.032457.c1044d4c.en.html x_refsource_MISC
https://bugs.exim.org/show_bug.cgi?id=2449 x_refsource_MISC
https://git.exim.org/exim.git/commit/478effbfd9c3cc5a627fc671d4bf94d13670d65f x_refsource_MISC
[oss-security] 20190928 Exim CVE-2019-16928 RCE using a heap-based buffer overflow mailing-list, x_refsource_MLIST
[oss-security] 20190928 Re: Exim CVE-2019-16928 RCE using a heap-based buffer overflow mailing-list, x_refsource_MLIST
[oss-security] 20190928 Re: Exim CVE-2019-16928 RCE using a heap-based buffer overflow mailing-list, x_refsource_MLIST
DSA-4536 vendor-advisory, x_refsource_DEBIAN
USN-4141-1 vendor-advisory, x_refsource_UBUNTU
[oss-security] 20190929 Re: Exim CVE-2019-16928 RCE using a heap-based buffer overflow mailing-list, x_refsource_MLIST
20190929 [SECURITY] [DSA 4536-1] exim4 security update mailing-list, x_refsource_BUGTRAQ
FEDORA-2019-006dfc94cd vendor-advisory, x_refsource_FEDORA
FEDORA-2019-e080507ba5 vendor-advisory, x_refsource_FEDORA
FEDORA-2019-d778bd4137 vendor-advisory, x_refsource_FEDORA
GLSA-202003-47 vendor-advisory, x_refsource_GENTOO
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-16928 government-resource