CVE-2021-3403 Use after free in ytnef

What is CVE-2021-3403?

CVE-2021-3403 is a high-severity use after free vulnerability in Fedoraproject Fedora, published on 4 Mar 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

Official description

In ytnef 1.9.3, the TNEFSubjectHandler function in lib/ytnef.c allows remote attackers to cause a denial-of-service (and potentially code execution) due to a double free which can be triggered via a crafted file.

Weakness: CWE-415, CWE-416

Which versions are affected by CVE-2021-3403?

It affects 3 products.

Products include Fedoraproject Fedora, Redhat Enterprise Linux, Ytnef Project Ytnef.

How do I fix CVE-2021-3403?

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-2021-3403 being exploited?

There is no known exploitation of CVE-2021-3403 in the wild and no public exploit code.

Other vulnerabilities in Fedoraproject Fedora

• CVE-2024-4577 PHP-CGI OS Command Injection Exploited Critical 9.8
• CVE-2021-39226 Grafana Authentication Bypass Exploited Critical 9.8
• CVE-2019-5544 VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Exploited Critical 9.8
• CVE-2024-4947 Google Chromium V8 Type Confusion Exploited Critical 9.6
• CVE-2024-4671 Google Chromium Visuals Use-After-Free Exploited Critical 9.6

All Fedoraproject Fedora vulnerabilities

Sources

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

Also known as DEBIAN-CVE-2021-3403, GHSA-4pxg-g29h-qqfc, UBUNTU-CVE-2021-3403.