CVE-2020-12783 Auth bypass in n/a

What is CVE-2020-12783?

CVE-2020-12783 is a high-severity authentication bypass vulnerability in Canonical Ubuntu Linux, published on 11 May 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Exim through 4.93 has an out-of-bounds read in the SPA authenticator that could result in SPA/NTLM authentication bypass in auths/spa.c and auths/auth-spa.c.

Weakness: CWE-125

Which versions are affected by CVE-2020-12783?

It affects 4 products.

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

How do I fix CVE-2020-12783?

Apply the vendor's patch.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2020-12783 being exploited?

There is no known exploitation of CVE-2020-12783 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 CLEANSTART-2025-NA80309, DEBIAN-CVE-2020-12783, DLA-2213-1, DSA-4687-1, GHSA-mqxr-gww5-9jhp, UBUNTU-CVE-2020-12783 and 1 more.