CVE-2021-3348

Name: CVE-2021-3348
Creator: NVD / NIST
Published: 2021-02-01T04:15:14.43+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7/10EPSS 0.25%

Last modified Jun 17, 2026

CVE-2021-3348 is a high-severity vulnerability rated 7/10 on the CVSS scale. nbd_add_socket in drivers/block/nbd.c in the Linux kernel through 5.10.12 has an ndb_queue_rq use-after-free that could be triggered by local attackers (with access to the nbd device) via an I/O request at a certain point during device setup, aka CID-b98e762e3d71.. EPSS estimates a 0.25% chance of exploitation in the next 30 days.

Description

nbd_add_socket in drivers/block/nbd.c in the Linux kernel through 5.10.12 has an ndb_queue_rq use-after-free that could be triggered by local attackers (with access to the nbd device) via an I/O request at a certain point during device setup, aka CID-b98e762e3d71.

Metrics

CVSS 3.1

7/10

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

EPSS Probability

0.25%

16.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	<= 5.10.12
Debian	Debian Linux	9.0

References

http://www.openwall.com/lists/oss-security/2021/02/01/1Mailing List, Patch, Third Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b98e762e3d71e893b221f871825dc64694cfb258Mailing List, Patch, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2021/03/msg00035.htmlThird Party Advisory
https://www.openwall.com/lists/oss-security/2021/01/28/3Mailing List, Patch, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/02/01/1Mailing List, Patch, Third Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b98e762e3d71e893b221f871825dc64694cfb258Mailing List, Patch, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2021/03/msg00035.htmlThird Party Advisory
https://www.openwall.com/lists/oss-security/2021/01/28/3Mailing List, Patch, Third Party Advisory

Timeline

Published: Feb 1, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3348?

How severe is CVE-2021-3348?

CVE-2021-3348 has a CVSS score of 7/10 (HIGH severity). The EPSS model estimates a 0.25% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3348?

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-2021-3348?

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

Scan your code now

Source: NVD / NIST