CVE-2021-40401 Use after free in Gerbv

What is CVE-2021-40401?

CVE-2021-40401 is a critical use after free vulnerability in Debian Debian Linux, published on 4 Feb 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A use-after-free vulnerability exists in the RS-274X aperture definition tokenization functionality of Gerbv 2.7.0 and dev (commit b5f1eacd) and Gerbv forked 2.7.1. A specially-crafted gerber file can lead to code execution. An attacker can provide a malicious file to trigger this vulnerability.

Weakness: CWE-252

Which versions are affected by CVE-2021-40401?

It affects 3 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Gerbv Project Gerbv.

How do I fix CVE-2021-40401?

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-2021-40401 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-40401 exists.

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 DEBIAN-CVE-2021-40401, GHSA-x68j-pwcm-v888, UBUNTU-CVE-2021-40401.