CVE-2018-6307 Use after free in LibVNC

What is CVE-2018-6307?

CVE-2018-6307 is a high-severity use after free vulnerability in Canonical Ubuntu Linux, published on 19 Dec 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

LibVNC before commit ca2a5ac02fbbadd0a21fabba779c1ea69173d10b contains heap use-after-free vulnerability in server code of file transfer extension that can result remote code execution.

Weakness: CWE-416

Which versions are affected by CVE-2018-6307?

It affects 3 products.

Products include Canonical Ubuntu Linux, Debian Debian Linux, Libvnc Project Libvncserver.

How do I fix CVE-2018-6307?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2018-6307 being exploited?

There is no known exploitation of CVE-2018-6307 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 DEBIAN-CVE-2018-6307, GHSA-862p-2jpg-8gg4, UBUNTU-CVE-2018-6307.