CVE-2021-3178 Path traversal in n/a

What is CVE-2021-3178?

CVE-2021-3178 is a medium-severity path traversal vulnerability in Debian Debian Linux, published on 19 Jan 2021. An attacker needs administrator access to exploit it, with no action from the victim.

Official description

fs/nfsd/nfs3xdr.c in the Linux kernel through 5.10.8, when there is an NFS export of a subdirectory of a filesystem, allows remote attackers to traverse to other parts of the filesystem via READDIRPLUS. NOTE: some parties argue that such a subdirectory export is not intended to prevent this attack; see also the exports(5) no_subtree_check default behavior

Weakness: CWE-22

Which versions are affected by CVE-2021-3178?

It affects 3 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Linux kernel.

How do I fix CVE-2021-3178?

Apply the vendor's patch.

Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.

Is CVE-2021-3178 being exploited?

There is no known exploitation of CVE-2021-3178 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-2021-3178, GHSA-7fjq-g87x-vg8r, UBUNTU-CVE-2021-3178.