CVE-2017-1000421 Use after free in n/a

What is CVE-2017-1000421?

CVE-2017-1000421 is a critical use after free vulnerability in Debian Debian Linux, published on 2 Jan 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Gifsicle gifview 1.89 and older is vulnerable to a use-after-free in the read_gif function resulting potential code execution

Weakness: CWE-416

Which versions are affected by CVE-2017-1000421?

It affects 2 products.

Products include Debian Debian Linux, Lcdf Gifsicle.

How do I fix CVE-2017-1000421?

Upgrade to a fixed version.

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-2017-1000421 being exploited?

There is no known exploitation of CVE-2017-1000421 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 DEBIAN-CVE-2017-1000421, DLA-1233-1, DSA-4084-1, GHSA-vp7h-g9mh-c77g, MGASA-2018-0086, UBUNTU-CVE-2017-1000421.