CVE-2018-16839 Memory corruption in curl:

Medium 4.3 Published 31 Oct 2018 Updated 15 Apr 2026

A buffer overrun in the SASL authentication code of the curl library allows attackers to cause a denial of service.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: Available

What is CVE-2018-16839?

CVE-2018-16839 is a medium-severity memory corruption vulnerability in Canonical Ubuntu Linux, published on 31 Oct 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Curl versions 7.33.0 through 7.61.1 are vulnerable to a buffer overrun in the SASL authentication code that may lead to denial of service.

Weakness: CWE-119, CWE-190, CWE-122

Which versions are affected by CVE-2018-16839?

It affects 3 products.

Linux distribution packages (12)

`curl` SUSE:Enterprise Storage 4	All versions	`7.37.0-37.37.1`
`curl` SUSE:Linux Enterprise Desktop 12 SP3	All versions	`7.37.0-37.37.1`
`curl` SUSE:Linux Enterprise Server 12 SP1-LTSS	All versions	`7.37.0-37.37.1`
`curl` SUSE:Linux Enterprise Server 12 SP2-BCL	All versions	`7.37.0-37.37.1`
`curl` SUSE:Linux Enterprise Server 12 SP2-LTSS	All versions	`7.37.0-37.37.1`
`curl` SUSE:Linux Enterprise Server 12 SP3	All versions	`7.37.0-37.37.1`
`curl` SUSE:Linux Enterprise Server 12-LTSS	All versions	`7.37.0-37.37.1`
`curl` SUSE:Linux Enterprise Server for SAP Applications 12 SP1	All versions	`7.37.0-37.37.1`
`curl` SUSE:Linux Enterprise Server for SAP Applications 12 SP2	All versions	`7.37.0-37.37.1`
`curl` SUSE:Linux Enterprise Server for SAP Applications 12 SP3	All versions	`7.37.0-37.37.1`
`curl` SUSE:Linux Enterprise Software Development Kit 12 SP3	All versions	`7.37.0-37.37.1`
`curl` SUSE:OpenStack Cloud 7	All versions	`7.37.0-37.37.1`

Products include Canonical Ubuntu Linux, Debian Debian Linux, Haxx Curl.

How do I fix CVE-2018-16839?

Upgrade to a fixed version.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2018-16839 being exploited?

There is no known exploitation of CVE-2018-16839 in the wild and no public exploit code.

All Canonical Ubuntu Linux vulnerabilities

Sources

Also known as ALPINE-CVE-2018-16839, CLEANSTART-2026-JA50765, CURL-CVE-2018-16839, DEBIAN-CVE-2018-16839, GHSA-g54v-fj63-pm34, SUSE-SU-2019:0996-1 and 1 more.