CVE-2021-3178

What it is

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

At a glance

Exploitability

Can be exploited over the network with an admin-level account. High risk of data exposure, data tampering.

Exploit odds

2.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-01-19 07:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 04:04 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 2.4% in the next 30 days (EPSS).
• Severity: 6.5 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-01-19 07:15 UTC

Last modified

2026-06-17 04:04 UTC

Exploit probability

2.4% · EPSS, next 30 days

Weakness

CWE-22 · Path traversal

Record status

Modified

Affected

• Linux Kernel ≤ 5.10.8
• Fedoraproject Fedora 33
• Debian Linux 9.0

Attack profile CVSS 3.1 · 6.5

Attack vector

Network

Complexity

Low

Privileges needed

High

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-3178.md and follow it. Check whether this project is affected by CVE-2021-3178. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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