CVE-2019-16928

Name: CVE-2019-16928
Creator: NVD / NIST
Published: 2019-09-27T21:15:10.017+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10Actively ExploitedEPSS 42.48%

Last modified Jun 17, 2026

CVE-2019-16928 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. CISA has confirmed active exploitation in the wild. EPSS estimates a 42.48% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

42.48%

98.5th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by Mar 17, 2022.

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Exim	Exim	>= 4.92, <= 4.92.2
Canonical	Ubuntu Linux	19.04
Debian	Debian Linux	10.0
Fedoraproject	Fedora	29
Fedoraproject	Fedora	30
Fedoraproject	Fedora	31

References

http://www.openwall.com/lists/oss-security/2019/09/28/1Exploit, Mailing List, Mitigation, Third Party Advisory
http://www.openwall.com/lists/oss-security/2019/09/28/2Exploit, Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2019/09/28/3Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2019/09/28/4Mailing List, Third Party Advisory
https://bugs.exim.org/show_bug.cgi?id=2449Issue Tracking, Patch, Vendor Advisory
https://git.exim.org/exim.git/commit/478effbfd9c3cc5a627fc671d4bf94d13670d65fPatch
https://lists.exim.org/lurker/message/20190927.032457.c1044d4c.en.htmlVendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EED7HM3MFIBAP5OIMJAFJ35JAJABTVSC/Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T3TJW4HPYH3O5HZCWGD6NSHTEBTTAPDC/Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UY6HPRW7MR3KBQ5JFHH6OXM7YCZBJCOB/Release Notes
https://seclists.org/bugtraq/2019/Sep/60Mailing List, Third Party Advisory
https://security.gentoo.org/glsa/202003-47Third Party Advisory
https://usn.ubuntu.com/4141-1/Third Party Advisory
https://www.debian.org/security/2019/dsa-4536Third Party Advisory
http://www.openwall.com/lists/oss-security/2019/09/28/1Exploit, Mailing List, Mitigation, Third Party Advisory
http://www.openwall.com/lists/oss-security/2019/09/28/2Exploit, Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2019/09/28/3Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2019/09/28/4Mailing List, Third Party Advisory
https://bugs.exim.org/show_bug.cgi?id=2449Issue Tracking, Patch, Vendor Advisory
https://git.exim.org/exim.git/commit/478effbfd9c3cc5a627fc671d4bf94d13670d65fPatch
https://lists.exim.org/lurker/message/20190927.032457.c1044d4c.en.htmlVendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EED7HM3MFIBAP5OIMJAFJ35JAJABTVSC/Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T3TJW4HPYH3O5HZCWGD6NSHTEBTTAPDC/Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UY6HPRW7MR3KBQ5JFHH6OXM7YCZBJCOB/Release Notes
https://seclists.org/bugtraq/2019/Sep/60Mailing List, Third Party Advisory
https://security.gentoo.org/glsa/202003-47Third Party Advisory
https://usn.ubuntu.com/4141-1/Third Party Advisory
https://www.debian.org/security/2019/dsa-4536Third Party Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-16928US Government Resource

Timeline

Published: Sep 27, 2019
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2019-16928?

How severe is CVE-2019-16928?

CVE-2019-16928 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 42.48% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2019-16928?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-16928?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST