CVE-2020-12673 Denial of service in n/a

What is CVE-2020-12673?

CVE-2020-12673 is a high-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 12 Aug 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

In Dovecot before 2.3.11.3, sending a specially formatted NTLM request will crash the auth service because of an out-of-bounds read.

Weakness: CWE-125

Which versions are affected by CVE-2020-12673?

It affects 4 products.

Products include Canonical Ubuntu Linux, Debian Debian Linux, Dovecot Dovecot, Fedoraproject Fedora.

How do I fix CVE-2020-12673?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2020-12673 being exploited?

There is no known exploitation of CVE-2020-12673 in the wild and no public exploit code.

Other vulnerabilities in Canonical Ubuntu Linux

• CVE-2020-11651 SaltStack Salt Authentication Bypass Exploited Critical 9.8
• CVE-2020-7247 OpenSMTPD Remote Code Execution Exploited Critical 9.8
• CVE-2019-16928 Exim Out-of-bounds Write Exploited Critical 9.8
• CVE-2018-6789 Exim Buffer Overflow Exploited Critical 9.8
• CVE-2015-2590 Oracle Java SE and Java SE Embedded Remote Code Execution Exploited Critical 9.8

All Canonical Ubuntu Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2020-12673, CLSA-2025-1758630391, CLSA-2025-1758645976, DEBIAN-CVE-2020-12673, GHSA-25jr-qm4x-mvhx, UBUNTU-CVE-2020-12673.