CVE-2021-3178

Name: CVE-2021-3178
Creator: NVD / NIST
Published: 2021-01-19T07:15:13.443+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 2.42%

Last modified Jun 17, 2026

CVE-2021-3178 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 2.42% chance of exploitation in the next 30 days.

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

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

EPSS Probability

2.42%

82.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-22

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	<= 5.10.8
Fedoraproject	Fedora	33
Debian	Debian Linux	9.0

References

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=51b2ee7d006a736a9126e8111d1f24e4fd0afaa6Mailing List, Patch, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2021/03/msg00010.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5SGB7TNDVQEOJ7NVTGX56UWHDNQM5TRC/
https://patchwork.kernel.org/project/linux-nfs/patch/20210111210129.GA11652%40fieldses.org/
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=51b2ee7d006a736a9126e8111d1f24e4fd0afaa6Mailing List, Patch, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2021/03/msg00010.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5SGB7TNDVQEOJ7NVTGX56UWHDNQM5TRC/
https://patchwork.kernel.org/project/linux-nfs/patch/20210111210129.GA11652%40fieldses.org/

Timeline

Published: Jan 19, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3178?

How severe is CVE-2021-3178?

CVE-2021-3178 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 2.42% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3178?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3178?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST