CVE-2021-4019 Heap-based Buffer Overflow in vim/vim

What is CVE-2021-4019?

CVE-2021-4019 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 1 Dec 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

vim is vulnerable to Heap-based Buffer Overflow

Weakness: CWE-787, CWE-122

Which versions are affected by CVE-2021-4019?

It affects 4 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Neovim Neovim, Vim Vim.

How do I fix CVE-2021-4019?

Apply the vendor's patch.

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

Is CVE-2021-4019 being exploited?

There is no known exploitation of CVE-2021-4019 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

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

Also known as ALPINE-CVE-2021-4019, AZL-6949, DEBIAN-CVE-2021-4019, GHSA-r79c-6hf5-2jjx, MGASA-2021-0545, UBUNTU-CVE-2021-4019.