CVE-2021-39257 Denial of service in n/a

What is CVE-2021-39257?

CVE-2021-39257 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 7 Sep 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A crafted NTFS image with an unallocated bitmap can lead to a endless recursive function call chain (starting from ntfs_attr_pwrite), causing stack consumption in NTFS-3G < 2021.8.22.

Weakness: CWE-674

Which versions are affected by CVE-2021-39257?

It affects 2 products.

Products include Debian Debian Linux, Tuxera Ntfs-3g.

How do I fix CVE-2021-39257?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2021-39257 being exploited?

There is no known exploitation of CVE-2021-39257 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 AZL-6762, DEBIAN-CVE-2021-39257, GHSA-c7hf-64rq-w8mm, UBUNTU-CVE-2021-39257.